Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| brome mosaic virus rna replication proteins 1a and 2a from a complex in vitro. | brome mosaic virus (bmv) is a positive-strand rna virus that encodes two rna replication proteins, the helicaselike 1a and the polymeraselike 2a. 1a and 2a share extensive sequence similarities with proteins encoded by many other members of the alphaviruslike superfamily. while further purifying enzymatically active rna-dependent rna polymerase from plants infected by bmv, we observed that 1a, 2a, and the polymerase activity all cofractionated through multiple independent purification steps. mor ... | 1992 | 1404594 |
| nucleotide sequence responsible for the synthesis of a truncated coat protein of brome mosaic virus strain atcc66. | the atcc66 strain of brome mosaic virus (bmv) (propagated at kyoto university) contained two types of coat protein in its virion whereas the russian strain of bmv has been known to contain a single coat protein; both strains have two initiation codons for coat protein in the same reading frame at the 5'-proximal end of the gene in rna 4. comparative studies on the nucleotide sequences of the atcc66 and russian strains of bmv demonstrated that in the atcc66 strain, two adjacent adenine residues w ... | 1992 | 1402800 |
| mrna amplification system by viral replicase in transgenic plants. | we have constructed transgenic tobacco plants (m1x2-fcp2ifn plants) expressing viral rna replication genes of brome mosaic virus (bmv) and bmv rna3 derivative (fcp2ifn) carrying the human gamma interferon (ifn-gamma) gene. in m1x2-fcp2ifn plants the rna3 derivative expressed from the integrated cdna was replicated and subgenomic rna (i.e. mrna of ifn-gamma) was produced by bmv replicase. the accumulation level of the mrna of ifn-gamma was approximately 5-fold higher than that by the cauliflower ... | 1993 | 8262204 |
| interference with brome mosaic virus replication by targeting the minus strand promoter. | sense and antisense strategies for interfering with the replication of brome mosaic virus (bmv) were examined. the effects of 200 nucleotide-long sense and antisense transcripts, corresponding to the viral 3' end (-) strand promoter, on the accumulation of progeny viral rnas were studied by co-inoculation with wildtype bmv rnas. progeny accumulation in barley protoplasts transfected with either sense or antisense transcripts of the (-) strand promoter and bmv rnas-1 and -2 was decreased by more ... | 1993 | 8245860 |
| la autoantigen enhances and corrects aberrant translation of poliovirus rna in reticulocyte lysate. | translation initiation on poliovirus rna occurs by internal binding of ribosomes to a sequence within the 5' untranslated region. we have previously characterized a hela cell protein, p52, that binds to a fragment of the poliovirus 5' untranslated region (k. meerovitch, j. pelletier, and n. sonenberg, genes dev. 3:1026-1034, 1989). here we report the purification of the hela p52. protein microsequencing identified p52 as la autoantigen. the la protein is a human antigen that is recognized by ant ... | 1993 | 8389906 |
| recombination and polymerase error facilitate restoration of infectivity in brome mosaic virus. | the trna-like structure present in the 3' noncoding region of each of the four virion rnas of brome mosaic virus possesses a conserved a-67-u-a-65 (67aua65) sequence. four mutations in this region (67uaa65, 67gaa65, and 67caa65, each with a double base change, and 67gua65, containing a single point mutation), previously shown in vitro to be defective in minus-strand promoter function, were introduced into full-length genomic rnas 2 and 3, and their replicative competence was analyzed in barley p ... | 1993 | 8419651 |
| bromovirus movement protein genes play a crucial role in host specificity. | monocot-adapted brome mosaic virus (bmv) and dicot-adapted cowpea chlorotic mottle virus (ccmv) are closely related bromoviruses with tripartite rna genomes. although rnas 1 and 2 together are sufficient for rna replication in protoplasts, systemic infection also requires rna3, which encodes the coat protein and the nonstructural 3a movement protein. we have previously shown with bromoviral reassortants that host specificity determinants in both viruses are encoded by rna3 as well as by rna1 and ... | 1993 | 7682628 |
| reduction of tobacco mosaic virus accumulation in transgenic plants producing non-functional viral transport proteins. | transgenic plants producing the 30k temperature-sensitive transport protein (tp) of tobacco mosaic virus (tmv) mutant ni2519 (affecting cell-to-cell transport) were found to: (i) be susceptible to wild-type tmv u1 at 24 degrees c (a permissive temperature for ni2519 tp), (ii) acquire a certain level of resistance to tmv u1 accumulation when maintained at 33 degrees c (a non-permissive temperature for ni2519 tp) and (iii) lose the resistance to wild-type tmv after their transfer from 33 degrees c ... | 1993 | 8509764 |
| contributions of the brome mosaic virus rna-3 3'-nontranslated region to replication and translation. | sequences upstream of the 3'-terminal trna-like structure of brome mosaic virus rnas have been predicted to fold into several stem-loop and pseudoknot structures. to elucidate the functional role of this upstream region, a series of deletions was made in cdna clones of rna-3, a genomic component not required for replication. these deletion mutants were transcribed in vitro and cotransfected with rna-1 and rna-2 into barley protoplasts. deletion of single stem-loop structures gave progeny retaini ... | 1993 | 7684465 |
| targeting of antisense dna: comparison of activity of anti-rabbit beta-globin oligodeoxyribonucleoside phosphorothioates with computer predictions of mrna folding. | to assess the usefulness of computer-assisted modeling of mrna as an aid in design of antisense dna, the efficiency of inhibition of translation of rabbit beta-globin mrna by various antisense sequences was compared with calculated structures of the mrna. the model obtained by consideration of 30 lowest-energy computer-simulated structures is consistent with the high accessibility of the aug initiation codon region known from digestion with nucleases and with previous antisense inhibition studie ... | 1993 | 8155975 |
| non-canonical substrates of aminoacyl-trna synthetases: the trna-like structure of brome mosaic virus genomic rna. | a 3-d model of the tyrosylable trna-like domain of the genomic brome mosaic virus rnas was built by computer modelling based on solution probing of the molecule with different chemical and enzymatic reagents. this model encompasses four major structural domains, including two peculiar substructures oriented perpendicularly and mimicking a trna structure, and a fifth domain which makes the connection with the rest of the viral rna. after recalling the different steps that led to the present struc ... | 1993 | 8199250 |
| partial purification and characterization of foxtail mosaic potexvirus rna-dependent rna polymerase. | the rna-dependent rna polymerase (rdrp) of foxtail mosaic virus (fmv) was partially purified from infected leaves of chenopodium quinoa. the membrane fraction of crude plant extracts contained most of the fmv rdrp activity. additional purification was obtained by solubilization of the rdrp using kcl and dodecyl-sucrose and by centrifugation through a glycerol gradient. the rna template endogenous to rdrp preparations could be removed using micrococcal nuclease but the resulting fraction was unab ... | 1993 | 8249292 |
| efficient production of human gamma interferon in tobacco protoplasts by genetically engineered brome mosaic virus rnas. | we succeeded in producing human gamma interferon (ifn-gamma) in tobacco protoplasts in quantity using genetically engineered brome mosaic virus (bmv strain atcc66). this strain of bmv produces two types of coat protein, a full-length coat protein (20k) and a truncated coat protein (19k) which are translated from the first and second initiation codons, respectively. we replaced the truncated coat protein gene with the ifn-gamma gene and synthesized bmv-ifn-gamma chimera rnas using an in vitro tra ... | 1993 | 8336117 |
| targeting the site of rna-rna recombination in brome mosaic virus with antisense sequences. | it has been postulated that local hybridizations between viral rnas can mediate recombination in brome mosaic virus (bmv) and in poliovirus. to test this model, a 3' fragment of bmv rna1 was inserted into the 3' noncoding sequence of bmv rna3 in an antisense orientation. this resulted in high-frequency nonhomologous crossovers at or near the hybridized region. insertion of the same rna1 fragment in a positive-sense orientation did not promote recombination. modification of the antisense insert b ... | 1993 | 8341643 |
| bromovirus rna replication and transcription require compatibility between the polymerase- and helicase-like viral rna synthesis proteins. | the positive-strand rna bromoviruses encode two nonstructural proteins, 1a and 2a, involved in rna-dependent rna replication. these proteins have extensive sequence similarities with methyltransferase, helicase, and polymerase proteins of other plant and animal viruses. 1a and 2a can also form a complex in vitro. to explore whether 1a-2a interaction is required for rna replication in vivo, we reassorted the 1a and 2a genes from two different bromoviruses, brome mosaic virus (bmv) and cowpea chlo ... | 1993 | 8230440 |
| evaluation of the use of antisense trna(met) as an inhibitor for eukaryotic protein synthesis. | we attempted to explore the use of antisense rnas against trna as an inhibitor of eukaryotic protein synthesis. for this purpose, antisense rna against the 5'-end half of the initiator trna of wheat germ was synthesized, and its effect on translation of the brome mosaic virus mrna was investigated in a wheat germ cell-free system. when the antisense rna against the 5'-end half of the initiator trna including the anticodon sequence was added at the concentration of 8 microm to the cell-free syste ... | 1993 | 8400802 |
| identification of domains in brome mosaic virus rna-1 and coat protein necessary for specific interaction and encapsidation. | even though many single-stranded rnas are present in the cytoplasm of infected cells, encapsidation by brome mosaic virus (bmv) coat protein is specific for bmv rna. although the highly conserved 3' region of each of the three bmv genomic rnas is an attractive candidate for the site of recognition by the coat protein, band shift and uv cross-linking assays in the presence of specific and nonspecific competitors revealed only nonspecific interactions. however, bmv rna-1 formed a retarded complex ... | 1993 | 8411342 |
| effect of tandem repeated aug codons on translation efficiency of eukaryotic mrna carrying a short leader sequence. | the effect on translation of multiple copies of the initiation codon aug at the initiation site in a eukaryotic mrna carrying a short leader sequence was tested in translation experiments in vitro. dna, corresponding to a chimeric mrna sequence consisting of the 5' leader region of brome mosaic virus (bmv) rna4 and the goat pre-alpha-lactalbumin mrna sequence, was prepared and transcribed in vitro using sp6 rna polymerase. site-directed mutagenesis was carried out to change the sequence around t ... | 1993 | 8479441 |
| minus sense transcripts of brome mosaic virus rna-3 intercistronic region interfere with viral replication. | interference with virus replication through the use of defective viral sequences is providing new insight to replication strategies and novel approaches for induced resistance. because replication of brome mosaic virus (bmv) is potentiated by the intercistronic region of rna-3, we examined the effect of adding various (-)sense rnas corresponding to this region in co-transfections with wild type bmv rnas. progeny accumulation in barley protoplasts transfected with rnas 1+2 was decreased by 90% in ... | 1993 | 8517022 |
| rna-dependent replication, transcription, and persistence of brome mosaic virus rna replicons in s. cerevisiae. | this paper shows that yeast can be a host for the replication of a higher eukaryotic viral genome. brome mosaic virus (bmv) is a member of the alphavirus-like superfamily of animal and plant positive strand rna viruses. yeast expressing bmv rna replication genes 1a and 2a support rna-dependent replication and transcription of bmv rna3 derivatives. rna3 derivatives with the coat gene replaced by a reporter gene expressed that gene in a fashion dependent on 1a and 2a expression in trans and on bmv ... | 1993 | 8458084 |
| characterization of a host protein associated with brome mosaic virus rna-dependent rna polymerase. | the association of host proteins with viral rna replication proteins has been reported for a number of (+)-strand rna viruses. however, little is known about the identity or function of these host proteins in viral replication. in this paper we report the characterization of a host protein associated with the rna-dependent rna polymerase (rdrp) from brome mosaic virus (bmv)-infected barley. a host protein was specifically and proportionally enriched with bmv rdrp activity through several purific ... | 1993 | 8434011 |
| solution structure of the 3'-end of brome mosaic virus genomic rnas. conformational mimicry with canonical trnas. | the conformation of the last 201 nucleotides located at the 3'-end of brome mosaic virus (bmv) rnas was investigated in solution using different chemical and enzymatic probes. bases were probed with dimethylsulfate (which methylates n-1 positions of a, n-3 positions of c and n-7 positions of g), a carbodiimide (which modifies n-1 positions of g and n-3 positions of u) and diethylpyrocarbonate (which modifies n-7 positions of a). ribonucleases t1, u2 and s1 were used to map unpaired nucleotides a ... | 1994 | 8289279 |
| targeting of the site of nonhomologous genetic recombination in brome mosaic virus. | the genome of brome mosaic virus (bmv) consists of three positive strand rna segments that share a high degree of sequence homology in the 3' noncoding region. the phenomenon of both homologous and nonhomologous intersegment rna-rna recombinant has been demonstrated within the 3' noncoding region of bmv rnas. it has been postulated that nonhomologous crossovers occur at local heteroduplexes formed between the recombining bmv rna substrates of the same polarity and that the formation of double-st ... | 1994 | 8032254 |
| common replication strategies emerging from the study of diverse groups of positive-strand rna viruses. | studies using brome mosaic virus (bmv), sindbis virus and poliovirus have provided evidence that disparate groups of plant and animal positive strand rna viruses have remarkably similar replication strategies. the conservation of several functional domains within virus-encoded nonstructural proteins implies that, although the precise character of these and interacting host components varies for each virus, they employ similar mechanisms for rna replication. for (+) strand replication, similariti ... | 1994 | 8032249 |
| molecular studies of genetic rna-rna recombination in brome mosaic virus. | 1994 | 8191956 | |
| amplification in vivo of brome mosaic virus rnas bearing 3' noncoding region from cucumber mosaic virus. | the 3' noncoding aminoacylatable regions of the three genomic rnas of brome mosaic (bmv) and cucumber mosaic (cmv) viruses are highly conserved and exhibit extensive similarities in their primary and secondary structures. to investigate the functional significance of these conserved features, the 3' 186 nucleotide sequence of fny-cmv rna3 was incorporated into the 3' end of full-length genomic bmv rna2 and rna3 and their replicative competence and infectivity were examined in barley protoplasts ... | 1994 | 8091683 |
| the role of the 3'-untranslated region of non-polyadenylated plant viral mrnas in regulating translational efficiency. | tobacco mosaic virus (tmv) is a positive-sense rna virus in which the single genomic rna functions as a messenger rna. it is a member of a class of plant viral rnas that are the only known non-polyadenylated mrnas in plants. the 3'-untranslated region (utr) of tmv genomic rna is the functional equivalent of a poly(a) tail in that it increases mrna stability and regulates translational efficiency. to determine whether the 3'-utr of other non-polyadenylated plant viral mrnas regulate translation, ... | 1994 | 8194747 |
| second-site mutations in the brome mosaic virus rna3 intercistronic region partially suppress a defect in coat protein mrna transcription. | an intercistronic oligo(a) tract is present in the genomic rna3 of all bromoviruses sequenced to date and, for brome mosaic virus (bmv), is known to function as an activating sequence in transcription of the subgenomic coat protein mrna, rna4. mutations able to partially compensate for removal of the oligo(a) from bmv rna3 were identified by obtaining spontaneous second-site revertants. the starting bmv rna3 mutant carried a deletion of 17 of 18 residues of the intercistronic oligo(a), resulting ... | 1994 | 8291227 |
| the nucleotide sequence of citrus leaf rugose ilarvirus rna-2. | the nucleotide sequence of citrus leaf rugose ilarvirus (cilrv) rna-2 consists of 2990 nucleotides and contains one open reading frame (orf) which encodes a deduced translation product of 832 amino acids with a calculated m(r) of 95,501 (95k). the 5' terminus of the rna has a m7gppp cap. both the nucleotide sequence of cilrv rna-2 and its translated polypeptide share homologies with the nucleotide sequence and translated polypeptide, respectively, of rna-2 of alfalfa mosaic virus (almv). the hom ... | 1994 | 7931176 |
| the nucleotide sequence of apple mosaic virus coat protein gene has no similarity with other bromoviridae coat protein genes. | a double-stranded cdna was synthesized from in vitro polyadenylated apple mosaic virus (apmv) rna 3 using oligo(dt) and sequence-specific primers, and was cloned into plasmid vectors. a set of overlapping cdna clones was used to determine the nucleotide sequence of rna 4. apmv rna 4 was found to contain an open reading frame (orf) of 666 nucleotides, which was flanked by 5' and 3' non-translated sequences of 55 and 264 nucleotides, respectively. the orf encoding the coat protein was identified b ... | 1994 | 7931177 |
| inhibition of brome mosaic virus (bmv) amplification in protoplasts from transgenic tobacco plants expressing replicable bmv rnas. | transgenic tobacco plants (v123 plants) expressing a set of full-length brome mosaic virus (bmv) genomic rnas from the cauliflower mosaic virus 35s promoter were produced. the accumulation level of bmv rnas in v123 plant cells was approximately 1% of that in nontransgenic tobacco protoplasts inoculated with bmv rnas. the level of bmv rna in v123 protoplasts did not increase after inoculating the protoplasts with bmv rnas, whereas v123 protoplasts supported the accumulation of cucumber mosaic vir ... | 1995 | 7595390 |
| mutational analysis of the coat protein gene of brome mosaic virus: effects on replication and movement in barley and in chenopodium hybridum. | the coat protein (cp) open reading frame (orf) of brome mosaic virus (bmv) has been mutated to study host-related cp functions in barley, a systemic host, and in chenopodium hybridum l. which supports both local lesion formation and systemic spread of bmv. to test the role of the n-terminal region of cp, mutants c1 to c3, which synthesized the cp lacking first seven amino acids, and mutant d1, which had trp 22 and thr 23 replaced with phe-gly-ser, were generated. c1 to c3 inhibited virus systemi ... | 1995 | 7772801 |
| mutations in the helicase-like domain of protein 1a alter the sites of rna-rna recombination in brome mosaic virus. | a system that uses engineered heteroduplexes to efficiently direct in vivo crossovers between brome mosaic virus (bmv) rna1 and rna3 (p. nagy and j. bujarski, proc. natl. acad. sci. usa 90:6390-6394, 1993) has been used to explore the possible involvement of bmv 1a protein, an essential rna replication factor, in rna recombination. relative to wild-type 1a, several viable amino acid insertion mutations in the helicase-like domain of bmv 1a protein affected the nature and distribution of crossove ... | 1995 | 7884905 |
| formation of brome mosaic virus rna-dependent rna polymerase in yeast requires coexpression of viral proteins and viral rna. | in this report we show that yeast expressing brome mosaic virus (bmv) replication proteins 1a and 2a and replicating a bmv rna3 derivative can be extracted to yield a template-dependent bmv rna-dependent rna polymerase (rdrp) able to synthesize (-)-strand rna from bmv (+)-strand rna templates added in vitro. this virus-specific yeast-derived rdrp mirrored the template selectivity and other characteristics of rdrp from bmv-infected plants. equivalent extracts from yeast expressing 1a and 2a but l ... | 1995 | 7761419 |
| host-specific alterations in viral rna accumulation and infection spread in a brome mosaic virus isolate with an expanded host range. | to facilitate studies of virus-host interaction and the determinants of viral host range, we constructed full-length cdna clones to all three genomic rnas of an unusual brome mosaic virus (bmv) isolate with an expanded host range. while other bmv strains, including the previously cloned m1 strain, systemically infect barley and other grasses but not legumes, the expanded-host-range isolate and the set of transcripts from its cdna clones, designated the m2 strain of bmv, systemically infect both ... | 1995 | 7853481 |
| the 3'-untranslated region of brome mosaic virus rna does not enhance translation of capped mrnas in vitro. | the translation enhancing ability of cis-acting 3'-terminal untranslated region (3'-utr) of brome mosaic virus (bmv) was examined. two chimeric mrna constructs translated in rabbit reticulocyte lysates contained the bmv coat protein (cp) gene and npti gene, respectively. it was shown that the 3'-utr of bmv rna enhanced the translational efficiency of uncapped but not capped messages. | 1995 | 7883048 |
| biological significance of the seven amino-terminal basic residues of brome mosaic virus coat protein. | inoculation of six brome mosaic virus (bmv) rna3 transcripts with defined deletions in the coat protein (cp) gene to three chenopodium spp demonstrated that synthesis of a functional, encapsidation-competent cp is required for the induction of local lesions. the bmv cp open reading frame contains two in-frame aug codons separated by seven amino acids, resulting in the synthesis of two cps (cp1 and cp2). to elucidate the biological significance of the n-terminal basic region of bmv cp, rna3 varia ... | 1995 | 7645235 |
| host-specificity restriction by bromovirus cell-to-cell movement protein occurs after initial cell-to-cell spread of infection in nonhost plants. | the nonstructural 3a protein of the positive-strand rna bromoviruses is required for infection spread in plants and is a crucial determinant of host specificity in systemic infection. to determine the paths of wild-type (wt) bromovirus infection spread, the step at which 3a mutants are arrested, and the nature of the host specificity associated with the 3a gene, we used in situ hybridization to examine infection spread by cowpea chlorotic mottle bromovirus (ccmv) and its derivatives at the level ... | 1995 | 7831782 |
| partial restoration of inactivated ribosomes with sodium borohydride or amino acids. | the aldehyde radical of ribose c1' at position 4324 in rat liver 28s rrna generated by rna n-glycosidase was either reduced to an hydroxyl group by sodium borohydride or converted into aldimine through a nucleophilic addition of amino acid used as a primary amine. analysis of the r-fragment of 28s rrna by polyacrylamide gel electrophoresis showed that the reduction of aldehyde to an hydroxyl group with sodium borohydride was highly specific. the protein synthesis activity of modified ribosomes w ... | 1995 | 7649291 |
| efficient system of homologous rna recombination in brome mosaic virus: sequence and structure requirements and accuracy of crossovers. | brome mosaic virus (bmv), a tripartite positive-stranded rna virus of plants engineered to support intersegment rna recombination, was used for the determination of sequence and structural requirements of homologous crossovers. a 60-nucleotide (nt) sequence, common between wild-type rna2 and mutant rna3, supported efficient repair (90%) of a modified 3' noncoding region in the rna3 segment by homologous recombination with wild-type rna2 3' noncoding sequences. deletions within this sequence in r ... | 1995 | 7983703 |
| a spontaneous mutation in the movement protein gene of brome mosaic virus modulates symptom phenotype in nicotiana benthamiana. | brome mosaic virus (bmv) is a positive-strand rna virus with a multipartite genome that causes symptomless infection in nicotiana benthamiana. we have isolated and characterized a strain of bmv that produced uniform vein chlorosis in systemically infected n. benthamiana. analysis of pseudorecombinants constructed by exchanging rna 1 and 2 and rna 3 components between wild-type (non-symptom-inducing) and vein chlorosis-inducing strains of bmv indicated that the genetic determinant for the inducti ... | 1995 | 7884924 |
| coding changes in the 3a cell-to-cell movement gene can extend the host range of brome mosaic virus systemic infection. | the m1 and m2 strains of brome mosaic virus (bmv) both systemically infect the monocot host barley, but only the m2 strain systemically infects the dicot cowpea line tvu-612. we have shown previously that this difference in host range maps primarily to rna3. to further characterize the role of rna3 in host specificity, a series of rna3 hybrids were tested, in inoculations with m1 rna1 and rna2, for ability to systemically infect tvu-612 cowpea. although all hybrids were amplified well in cowpea ... | 1995 | 8553548 |
| interaction of host proteins with the plus-strand promoter of brome mosaic virus rna-2. | the binding of five barley proteins (mr: 37, 36, 35, 34, and 30 kda) to the icr2 motif present at the 5' end of brome mosaic virus (bmv) rna-2 was identified using uv cross-linking. evidence that the interaction is specific included the observation that these proteins did not recognize a similar-size rna fragment transcribed from a nonviral (beta-glucuronidase) gene, nor did they bind to the 3' end of the plus strand of rna-3. replication-defective bmv rna-2 mutants bearing substitution mutation ... | 1995 | 8553568 |
| biochemical and genetic analyses of the interaction between the helicase-like and polymerase-like proteins of the brome mosaic virus. | replication of the three positive-strand genomic rnas of brome mosaic virus requires the activities of the helicase-like 1a and the polymerase-like 2a proteins. one hundred fifteen amino acids of the 2a n-terminus and the 1a helicase-like region of over 50 kda are both necessary and sufficient for 1a-2a interaction. requirement of the large size of the 1a helicase-like domain suggests that higher order structures might be necessary for the protein's interaction with 2a. to explore the structural ... | 1995 | 8525639 |
| foreign complementary sequences facilitate genetic rna recombination in brome mosaic virus. | we have demonstrated that local antisense sequences can mediate genetic recombination within the 3' noncoding region among brome mosaic virus (bmv) rnas (p. nagy and j. j. bujarski, 1993, proc. natl. acad. sci. usa 90, 6390-6394). here we show that foreign complementary inserts can direct crossovers between bmv rna3 components within an internal region. a 170-nt polynucleotide derived from the cowpea chlorotic mottle virus (ccmv) rna3 was inserted just upstream of the initiation codon of the bmv ... | 1995 | 11831722 |
| thermodynamic prediction of conserved secondary structure: application to the rre element of hiv, the trna-like element of cmv and the mrna of prion protein. | an algorithm for prediction of conserved secondary structure of single-stranded rna is presented. for each rna of a set of homologous rnas optimal and suboptimal secondary structures are calculated and stored in a base-pair probability matrix. a multiple sequence alignment is performed for the set of rnas. the resulting gaps are introduced into the individual probability matrices. these homologous probability matrices are summed to give a consensus probability matrix emphasizing the conserved se ... | 1996 | 8637012 |
| homologous rna recombination in brome mosaic virus: au-rich sequences decrease the accuracy of crossovers. | brome mosaic virus, a tripartite positive-stranded rna virus of plants, was used for the determination of sequence requirements of imprecise (aberrant) homologous recombination. a 23-nucleotide (nt) region that included a 6-nt uuaaaa sequence (designated the au sequence) common between wild-type rna2 and mutant rna3 supported both precise and imprecise homologous recombination, though the latter occurred with lower frequency. doubling the length of the 6-nt au sequence in rna3 increased the inci ... | 1996 | 8523555 |
| usefulness of functional and structural solution data for the modeling of trna-like structures. | structures of large rnas are not easily solved by x-ray crystallography or by nmr spectroscopy. this paper reviews the alternate methodology based on enzymatic and chemical mapping data collected on rnas combined with graphical modeling for the construction of three-dimensional models. the different steps that lead to the establishment of the models are critically discussed. it is shown how the correctness of an rna model can be strengthened by establishing correlations between the structure and ... | 1996 | 8786997 |
| in vitro translation and translocation of apolipoprotein b in a cell-free system from hepg2 cells. | an mrna-dependent cell-free system has been developed from hepg2 cells by hydrolysis of endogenous mrna with micrococcal nuclease. when supplied with rna extracted from hepg2 cells, the system synthesized liver specific proteins such as albumin and apolipoprotein b100. significant amounts of microsomes were also detected in the lysate by measuring nadh-cytochrome c reductase activity and ultracentrifugation. protease protection assays showed the capability of the hepg2 lysate to translocate newl ... | 1996 | 8941365 |
| a single codon change in a conserved motif of a bromovirus movement protein gene confers compatibility with a new host. | brome mosaic virus (bmv) and cowpea chlorotic mottle virus (ccmv) are closely related bromoviruses with tripartite rna genomes, but distinct host ranges: bmv systemically infects the monocot barley, while ccmv systemically infects the dicot cowpea. we have previously shown that in approximately 10% of inoculated cowpea plants, a ccmv hybrid [ccmv(b3a)] with the 3a cell-to-cell movement protein gene replaced by that of cowpea-nonadapted bmv directs systemic infections, which are caused by seconda ... | 1996 | 8806564 |
| the mode of action of hirsutellin a on eukaryotic cells. | a 16-kda protein toxin was purified from hirsutella thompsonii var thompsonii and named hirsutellin a (hta). at 0.5 and 5.0 microm concentrations, hta caused detectable cytopathic effects on spodoptera frugiperda cells (sf-9) within 2-4 hr and completely inhibited sf-9 cell growth at 4 days posttreatment. electron microscope data showed that the hta treated sf-9 cells became hypotrophied and internal organelles and cell membranes were disrupted. at the same concentration, hta effectively inhibit ... | 1996 | 8812603 |
| molecular studies on bromovirus capsid protein. i. characterization of cell-to-cell movement-defective rna3 variants of brome mosaic virus. | to evaluate the extent to which brome mosaic virus (bmv) coat protein (cp) gene is involved in the process of cell-to-cell movement. chenopodium quinoa plants were coinoculated with bmv wild-type rnas 1 and 2 and a rna3 variant containing either the beta-glucuronidase (gus) gene in place of cp (b3/cp-gus), to be subjected to gus analysis, or a deletion in the cp gene to be analyzed by fluorescence in situ hybridization (fish). irrespective of time postinoculation, gus expressed from the subgenom ... | 1996 | 8955048 |
| phosphorylation of plant eukaryotic initiation factor-2 by the plant-encoded double-stranded rna-dependent protein kinase, ppkr, and inhibition of protein synthesis in vitro. | regulation of protein synthesis by eukaryotic initiation factor-2alpha (eif-2alpha) phosphorylation is a highly conserved phenomenon in eukaryotes that occurs in response to various stress conditions. protein kinases capable of phosphorylating eif-2alpha have been characterized from mammals and yeast. however, the phenomenon of eif2-alpha-mediated regulation of protein synthesis and the presence of an eif-2alpha kinase has not been demonstrated in higher plants. we show that plant eif-2alpha (pe ... | 1996 | 8626809 |
| molecular studies on bromovirus capsid protein. ii. functional analysis of the amino-terminal arginine-rich motif and its role in encapsidation, movement, and pathology. | the n-terminal region of the brome mosaic bromovirus (bmv) coat protein (cp) contains an arginine-rich motif that is conserved among plant and nonplant viruses and implicated in binding the rna during encapsidation. to elucidate the functional significance of this conserved motif in the bmv cp, a series of deletions encompassing the arginine-rich motif was introduced into a biologically active clone of bmv rna3, and their effect on replication, encapsidation, and infection in plants was examined ... | 1996 | 8955049 |
| initiation of (-)-strand rna synthesis catalyzed by the bmv rna-dependent rna polymerase: synthesis of oligonucleotides. | rna replication, a process of fundamental importance for pathogenesis by many viruses, remains poorly understood at the mechanistic level because relatively few of the responsible enzymes have been purified and characterized biochemically. partially purified rna-dependent rna polymerase (rdrp) from brome mosaic virus (bmv)-infected barley leaves is able to synthesize (-)-strand rnas from input (+)-strand templates. in resolving rdrp products generated during (-)-strand bmv rna synthesis, we foun ... | 1996 | 8941317 |
| brome mosaic virus helicase- and polymerase-like proteins colocalize on the endoplasmic reticulum at sites of viral rna synthesis. | the helicase-like 1a and polymerase-like 2a proteins of brome mosaic virus (bmv) are required for viral rna replication in vivo, are present in membrane-bound viral rna polymerase extracts, and share conservation with the many other members of the alphavirus-like superfamily. to better understand bmv rna replication and bmv-host interactions, we used confocal microscopy and double-label immunofluorescence to determine and compare the sites of 1a, 2a, and nascent viral rna accumulation in bmv-inf ... | 1996 | 8971020 |
| initiation of minus-strand rna synthesis by the brome mosaicvirus rna-dependent rna polymerase: use of oligoribonucleotide primers. | various dna- and rna-dependent rna polymerases have been reported to use oligoribonucleotide primers to initiate nucleic acid synthesis. for the brome mosaic virus rna-dependent rna polymerase (rdrp), we determined that in reactions performed with limited gtp concentrations, minus-strand rna synthesis can be stimulated by the inclusion of guanosine monophosphate or specific oligoribonucleotides. furthermore, guanylyl-3',5'-guanosine (gpg) was incorporated into minus-strand rna and increased the ... | 1996 | 8794323 |
| rotavirus vp1 alone specifically binds to the 3' end of viral mrna, but the interaction is not sufficient to initiate minus-strand synthesis. | recent studies have shown that disrupted (open) rotavirus cores have an associated replicase activity which supports the synthesis of dsrna from viral mrna in a cell-free system (d. chen, c. q.-y. zeng, m. j. wentz, m. gorziglia, m. k. estes, and r. f. ramig, j. virol. 68:7030-7039, 1994). to determine which of the core proteins, vp1, vp2, or vp3, recognizes the template mrna during rna replication, sa11 open cores were incubated with 32p-labeled rna probes of viral and nonviral origin and the r ... | 1996 | 8892917 |
| the polymerase-like core of brome mosaic virus 2a protein, lacking a region interacting with viral 1a protein in vitro, maintains activity and 1a selectivity in rna replication. | brome mosaic virus (bmv), a member of the alphavirus-like super-family of positive-strand rna viruses, encodes two proteins required for viral rna replication: 1a and 2a. 1a contains m7g methyltransferase- and helicase-like domains, while 2a contains a polymerase (pol)-like core flanked by n- and c-terminal extensions. genetic studies show that bmv rna replication requires 1a-2a compatibility implying direct or indirect 1a-2a interaction in vivo. in vitro, la interacts with the n-terminal 125-am ... | 1996 | 8676500 |
| complementation of a potato virus x mutant mediated by bombardment of plant tissues with cloned viral movement protein genes. | microprojectile bombardment was used to examine the transport function of the 25 kda movement protein (mp) encoded in the triple gene block of potato virus x (pvx). a 25 kda mp-defective full-length cloned pvx genome carrying a beta-glucuronidase (gus) reporter gene was co-bombarded with 35s promoter constructs containing either the 25 kda mp gene of wild-type pvx, the mp gene of either of two tobamoviruses (tomato mosaic virus or crucifer tobamovirus), red clover necrotic mosaic dianthovirus (r ... | 1997 | 9267010 |
| tubule-forming capacity of the movement proteins of alfalfa mosaic virus and brome mosaic virus. | the structural phenotype of the movement proteins (mps) of two representatives of the bromoviridae, alfalfa mosaic virus (amv) and brome mosaic virus (bmv), was studied in protoplasts. immunofluorescence microscopy showed that the mps of these viruses, for which there has been no evidence of a tubule-guided mechanism, assemble into long tubular structures at the surface of the infected protoplast. electron microscopy and immunogold analysis confirmed the presence of both mp and virus particles i ... | 1997 | 9267012 |
| analysis of the interaction of viral rna replication proteins by using the yeast two-hybrid assay. | the yeast two-hybrid system has been a useful tool in the genetic evaluation of protein-protein interactions. however, the biological relevance of these two-hybrid interactions to viral positive-strand rna replication has not been demonstrated. the brome mosaic virus (bmv) system has been characterized extensively both genetically and biochemically, providing numerous mutations in the bmv 1a helicase-like and 2a polymerase-like proteins. we have tested wild-type 1a and 18 insertion mutations of ... | 1997 | 9311832 |
| structure-based rationale for the rescue of systemic movement of brome mosaic virus by spontaneous second-site mutations in the coat protein gene. | we describe spontaneous second-site reversions within the coat protein open reading frame that rescue the systemic-spread phenotype and increase virion stability of a mutant of brome mosaic virus. based on the crystal structure of the related cowpea chlorotic mottle virus, we show that the modified residues are spatially clustered to affect the formation of hexamers and pentamers and therefore virion stability. | 1997 | 9032390 |
| a mutation in the putative rna polymerase gene inhibits nonhomologous, but not homologous, genetic recombination in an rna virus. | brome mosaic bromovirus (bmv), a positive-stranded rna virus, supports both homologous and nonhomologous rna recombinations. two bmv (temperature-sensitive) mutants with alterations in the 2a protein, the putative rna polymerase component of the viral replicase, were tested for their ability to support both types of recombination. here we report that one of these mutants with the leu-486 substituted by phe did not support nonhomologous recombination. effect on homologous recombination was mainly ... | 1997 | 9050907 |
| yeast mutations in multiple complementation groups inhibit brome mosaic virus rna replication and transcription and perturb regulated expression of the viral polymerase-like gene. | brome mosaic virus (bmv), a member of the alphavirus-like superfamily of positive-strand rna viruses, encodes two proteins, 1a and 2a, that interact with each other, with unidentified host proteins, and with host membranes to form the viral rna replication complex. yeast expressing 1a and 2a support replication and subgenomic mrna synthesis by bmv rna3 derivatives. using a multistep selection and screening process, we have isolated yeast mutants in multiple complementation groups that inhibit bm ... | 1997 | 9391109 |
| molecular studies on bromovirus capsid protein. iv. coat protein exchanges between brome mosaic and cowpea chlorotic mottle viruses exhibit neutral effects in heterologous hosts. | two members of the bromovirus group, brome mosaic virus (bmv) and cowpea chlorotic mottle virus (ccmv), selectively infect barley and cowpea, respectively, and also differ in their ability to systemically infect a common permissive host, chenopodium quinoa. ccmv is confined to inoculated leaves of c. quinoa, whereas bmv causes rapid systemic mottling. to examine whether host-specific determinants for systemic movement of bmv and ccmv in each of these hosts are localized in the coat protein (cp), ... | 1997 | 9400617 |
| engineering of homologous recombination hotspots with au-rich sequences in brome mosaic virus. | previously, we observed that crossovers sites of rna recombinants clustered within or close to au-rich regions during genetic recombination in brome mosaic bromovirus (bmv) (p. d. nagy and j. j. bujarski. j. virol. 70:415-426, 1996). to test whether au-rich sequences can facilitate homologous recombination, au-rich sequences were introduced into parental bmv rnas (rna2 and rna3). these insertions created a homologous rna2-rna3 recombination hotspot. two other au-rich sequences also supported hig ... | 1997 | 9094655 |
| minimal templates directing accurate initiation of subgenomic rna synthesis in vitro by the brome mosaic virus rna-dependent rna polymerase. | short regions of (-)-strand brome mosaic virus (bmv) rna3, proscripts, were shown to direct accurate in vitro synthesis of (+)-strand subgenomic rna by the bmv rna-dependent rna polymerase (rdrp), facilitating characterization of the sequences and/or structures directing subgenomic rna synthesis. proscripts retaining fewer than 8-nt of an 18-nt polyuridylate tract located just upstream of the core promoter sequence (french r, ahlquist p, 1988, j virol 62:2411-2420; marsh le, dreher tw, hall tc, ... | 1997 | 9174098 |
| effects of aspirin on nitric oxide formation and de novo protein synthesis by rinm5f cells and rat islets. | aspirin and aspirin-like drugs are the most commonly indicated agents for the treatment of inflammation. mechanisms of action for these drugs, however, are not clearly understood. in this study, we examined the effects of aspirin on production of nitric oxide (no), a proinflammatory mediator, and show that aspirin inhibits no production by transformed pancreatic beta cells (rinm5f) and rat islets in a concentration-dependent manner with an ic50 value of approximately 3 mm. therapeutic concentrat ... | 1997 | 9281601 |
| molecular studies on bromovirus capsid protein. iii. analysis of cell-to-cell movement competence of coat protein defective variants of cowpea chlorotic mottle virus. | to determine whether the role of coat protein (cp) in cell-to-cell movement of dicot-adapted cowpea chlorotic mottle bromovirus (ccmv) is distinct from that of monocot-adapted brome mosaic bromovirus (bmv), two reporter genes, beta-glucuronidase (gus) and enhanced green fluorescent protein (egfp), were substituted for the cp in a biologically active clone of ccmv rna3 (c3). primary leaves of nicotiana benthamiana, chenopodium quinoa, and cowpea were co-inoculated with wild-type (wt) ccmv rna 1 a ... | 1997 | 9191853 |
| rna synthesis by the brome mosaic virus rna-dependent rna polymerase: transition from initiation to elongation. | the initiation and elongation phases of (-)-strand rna synthesis in vitro by the brome mosaic virus rna-dependent rna polymerase (rdrp) are differentially sensitive to inhibitors. in an attempt to characterize further the transition rdrp makes from initiation to elongation, we determined the conditions needed to pause the ternary complex and complete only one round of rna synthesis. during the transition we were able to discern step-wise increases in the affinity of rdrp for rna by measuring sen ... | 1997 | 9201217 |
| in vivo dna expression of functional brome mosaic virus rna replicons in saccharomyces cerevisiae. | to facilitate manipulation of brome mosaic virus (bmv) rna replicons in saccharomyces cerevisiae and for yeast genetic analysis of bmv rna replication, gene expression, and host interactions, we constructed dna plasmids from which bmv rna3 and rna3 derivatives can be transcribed in vivo from the galactose-inducible yeast gal1 promoter and terminated by a self-cleaving ribozyme at or near their natural 3' ends. in galactose-induced yeast harboring such plasmids, expression of bmv rna replication ... | 1997 | 9311863 |
| sequence-specific recognition of a subgenomic rna promoter by a viral rna polymerase. | rna templates of 33 nucleotides containing the brome mosaic virus (bmv) core subgenomic promoter were used to determine the promoter elements recognized by the bmv rna-dependent rna polymerase (rdrp) to initiate rna synthesis. nucleotides at positions -17, -14, -13, and -11 relative to the subgenomic initiation site must be maintained for interaction with the rdrp. changes to every other nucleotide at these four positions allow predictions for the base-specific functional groups required for rdr ... | 1997 | 9326593 |
| the effect of histone-mrna interaction in protein synthesis. | the effect of lysine-rich and arginine-rich histones on selective inhibition of translation of mrnas of tobacco mosaic virus (tmv), brome mosaic virus (bmv) and luciferase, in rabbit reticulocyte (rrl) was evaluated. nuclease-treated rrl were supplemented with an appropriate mrna and incubated with lysine-rich or arginine-rich histones at 5 and 2.5 micrograms/100 microliters lysate at 30 degrees c. protein synthesis was measured as incorporation of 3h-leucine into protein for 24 min. the lysine- ... | 1997 | 9693888 |
| deletion of the c-terminal 33 amino acids of cucumber mosaic virus movement protein enables a chimeric brome mosaic virus to move from cell to cell. | the movement protein (mp) gene of brome mosaic virus (bmv) was precisely replaced with that of cucumber mosaic virus (cmv). infectivity tests of the chimeric bmv on chenopodium quinoa, a permissive host for cell-to-cell movement of both bmv and cmv, showed that the chimeric bmv failed to move from cell to cell even though it replicated in protoplasts. a spontaneous mutant of the chimeric bmv that displayed cell-to-cell movement was subsequently obtained from a local lesion during one of the expe ... | 1997 | 9032362 |
| nucleic acid-binding properties and subcellular localization of the 3a protein of brome mosaic bromovirus. | brome mosaic bromovirus (bmv) 3a protein is required for cell-to-cell movement of the virus in host plants. the bmv 3a protein (b3a) was produced in escherichia coli using an expression vector. gel retardation analysis and uv cross-linking experiments demonstrated that b3a bound single-stranded rna cooperatively without sequence specificity. binding competition analysis showed that b3a bound to single-stranded nucleic acids more strongly than to double-stranded nucleic acids. deletion mutagenesi ... | 1998 | 9603343 |
| resected rna pseudoknots and their recognition by histidyl-trna synthetase. | duplexes constituted by closed or open rna circles paired to single-stranded oligonucleotides terminating with 3'-ccaoh form resected pseudoknots that are substrates of yeast histidyl-trna synthetase. design of this rna fold is linked to the mimicry of the pseudoknotted amino acid accepting branch of the trna-like domain from brome mosaic virus, known to be charged by tyrosyl-trna synthetases, with rna minihelices recapitulating accepting branches of canonical trnas. prediction of the histidylat ... | 1998 | 9724720 |
| mutations in the n terminus of the brome mosaic virus polymerase affect genetic rna-rna recombination. | previously, we have observed that mutations in proteins 1a and 2a, the two virally encoded components of the brome mosaic virus (bmv) replicase, can affect the frequency of recombination and the locations of rna recombination sites (p. d. nagy, a. dzianott, p. ahlquist, and j. j. bujarski, j. virol. 69:2547-2556, 1995; m. figlerowicz, p. d. nagy, and j. j. bujarski, proc. natl. acad. sci. usa 94:2073-2078, 1997). also, it was found before that the n-terminal domain of 2a, the putative rna polyme ... | 1998 | 9765466 |
| interactions between the structural domains of the rna replication proteins of plant-infecting rna viruses. | brome mosaic virus (bmv), a positive-strand rna virus, encodes two replication proteins: the 2a protein, which contains polymerase-like sequences, and the 1a protein, with n-terminal putative capping and c-terminal helicase-like sequences. these two proteins are part of a multisubunit complex which is necessary for viral rna replication. we have previously shown that the yeast two-hybrid assay consistently duplicated results obtained from in vivo rna replication assays and biochemical assays of ... | 1998 | 9696810 |
| moieties in an rna promoter specifically recognized by a viral rna-dependent rna polymerase. | rnas 33 nucleotides in length can direct accurate initiation of subgenomic rna synthesis by the brome mosaic virus rna-dependent rna polymerase (rdrp), provided that the native sequences are maintained at five positions: -17, -14, -13, -11, and the +1 initiation site. the functional groups in the bases of these essential nucleotides required to interact with rdrp were examined by using chemically synthesized rnas containing base analogs at each of the five positions. analysis using a template co ... | 1998 | 9751714 |
| sequences 5' of the conserved trna-like promoter modulate the initiation of minus-strand synthesis by the brome mosaic virus rna-dependent rna polymerase. | each of the brome mosaic virus (bmv) genomic rnas contains a conserved trna-like structure that is sufficient to direct minus-strand rna synthesis in vitro. the trna-like promoters, tb1 and tb3, direct approximately equal amounts of synthesis in vitro. however, 5' sequences were found to affect the amount of minus-strand synthesis, suggesting that sequences beyond the trna-like structure are important in moderating minus-strand synthesis. consistent with this, sequences upstream the trna-like st ... | 1998 | 9878626 |
| subgenomic rna promoters dictate the mode of recognition by bromoviral rna-dependent rna polymerases. | both the brome mosaic virus (bmv) and cowpea chlorotic mottle virus (ccmv) rna-dependent rna polymerases (rdrps) were found to recognize the bmv core subgenomic promoter in the same manner, requiring specific functional groups at positions -17, -14, -13, and -11 relative to the subgenomic initiation site (+1). for ccmv subgenomic rna synthesis, both rdrps required the same nucleotides and four additional nucleotides at positions -20, -16, -15, and -10. the -20 nucleotide is partially responsible ... | 1998 | 9875310 |
| mechanistic analysis of rna synthesis by rna-dependent rna polymerase from two promoters reveals similarities to dna-dependent rna polymerase. | the brome mosaic virus (bmv) rna-dependent rna polymerase (rdrp) directs template-specific synthesis of (-)-strand genomic and (+)-strand subgenomic rnas in vitro. although the requirements for (-)-strand rna synthesis have been characterized previously, the mechanism of subgenomic rna synthesis has not. mutational analysis of the subgenomic promoter revealed that the +1 cytidylate and the +2 adenylate are important for rna synthesis. unlike (-)-strand rna synthesis, which required only a high g ... | 1998 | 9630251 |
| rna recombination in brome mosaic virus, a model plus strand rna virus. | studies on the molecular mechanism of genetic recombination in rna viruses have progressed at the time when experimental systems of efficient recombination crossovers were established. the system of brome mosaic virus (bmv) represents one of the most useful and most advanced tools for investigation of the molecular aspects of the mechanism of rna-rna recombination events. by using engineered bmv rna components, the occurrence of both homologous and nonhomologous crosses were demonstrated among t ... | 1998 | 10397334 |
| properties of a virus causing mosaic and leaf curl disease of celosia argentea l. in nigeria. | a sap transmissible virus, causing mosaic and leaf curl disease of celosia argentea, was isolated at vegetable farms in amuwo odofin, tejuoso, and abule ado, lagos, nigeria. the virus had a restricted host range confined to a few species of the amaranthaceae, chenopodiaceae and solanaceae families. it failed to infect several other species of the aizoaceae, brassicaceae, cucurbitaceae, fabaceae, lamiaceae, malvaceae, poaceae and tiliaceae families. the virus was transmitted in a non-persistent m ... | 1998 | 9842442 |
| characterization of the brome mosaic virus movement protein expressed in e. coli. | the biochemical and functional properties of the movement protein (mp) of brome mosaic virus (bmv) were investigated. expression and purification of the bmv mp from escherichia coli resulted in a pure and soluble protein preparation. sucrose gradient centrifugation revealed that bmv mp forms oligomers consisting of two or more copies but no higher order multimers even when different ionic strengths and phs were applied. nitro-cellulose filter binding and gel retardation studies showed that in vi ... | 1998 | 9514964 |
| silencing homologous rna recombination hot spots with gc-rich sequences in brome mosaic virus. | it has been observed that au-rich sequences form homologous recombination hot spots in brome mosaic virus (bmv), a tripartite positive-stranded rna virus of plants (p. d. nagy and j. j. bujarski, j. virol. 71:3799-3810, 1997). to study the effect of gc-rich sequences on the recombination hot spots, we inserted 30-nucleotide-long gc-rich sequences downstream of au-rich homologous recombination hot spot regions in parental bmv rnas (rna2 and rna3). although these insertions doubled the length of s ... | 1998 | 9445008 |
| transfer rna identity rules and conformation of the tyrosine trna-like domain of bmv rna imply additional charging by histidine and valine. | this paper reports the first example of a triple aminoacylation specificity of a viral trna-like domain. these findings were based on structural studies on the brome mosaic virus (bmv) trna-like domain (felden et al., 1994, j. mol. biol. 235, 508-531) together with knowledge on trna aminoacylation identity rules suggesting potential histidinylation and valylation capacities of the viral rna in addition to its already known tyrosylation ability. here, both predictions are demonstrated by in vitro ... | 1998 | 9480825 |
| the preparation of rna-dependent rna polymerase complex from virus infected plants. | cucumber mosaic virus (cmv) is an icosahedrion plant virus and contains three different single-stranded positive sense genomic rnas. the very 3' ends of each of the genomic rnas can fold into a trna-like structure. based on the structural analysis of the 3' trna-like structure of the brome mosaic virus (bmv), we superimposed and redrew the 3' trna-like structure of cmv. we homogenized virus infected or healthy tobacco leaves with polytron and carried out low speed centrifugation twice and ultra- ... | 1998 | 9615471 |
| brome mosaic virus rna replication protein 1a dramatically increases in vivo stability but not translation of viral genomic rna3. | brome mosaic virus (bmv), a positive-strand rna virus in the alphavirus-like superfamily, encodes two rna replication proteins: 1a, which contains a helicase-like domain and a domain implicated in rna capping, and 2a, which contains a polymerase-like domain. to further explore their functions, we expressed 1a and 2a individually and together in yeast also expressing replicatable transcripts of bmv genomic rna3. complementing prior results that 1a and 2a are required jointly for positive-strand r ... | 1998 | 9482867 |
| a core promoter hairpin is essential for subgenomic rna synthesis in alfalfa mosaic alfamovirus and is conserved in other bromoviridae. | the nucleotide sequence immediately in front of the initiation site for subgenomic rna 4 synthesis on rna 3 minus strand, which has been proved to function as a core promoter, was inspected for secondary structure in 26 species of the plant virus family bromoviridae. in 23 cases a stable hairpin could be predicted at a distance of 3 to 8 nucleotides from the initiation site of rna 4. this hairpin contained several conserved nucleotides that are essential for core promoter activity in brome mosai ... | 1998 | 9926399 |
| defective movement of viruses in the family bromoviridae is differentially complemented in nicotiana benthamiana expressing tobamovirus or dianthovirus movement proteins. | abstract taxonomically distinct tobacco mosaic tobamovirus (tmv), red clover necrotic mosaic dianthovirus (rcnmv), cucumber mosaic cucumovirus (cmv), brome mosaic bromovirus (bmv), and cowpea chlorotic mottle bromovirus (ccmv) exhibit differences in their host range. each of these viruses encodes a functionally similar nonstructural movement protein (mp) that is essential for cell-to-cell movement of a progeny virus. despite the lack of significant amino acid identity among the mps of cmv, tmv, ... | 1998 | 18944938 |
| genotypic and phenotypic analysis of bromovirus adaptive mutants derived from a single plant. | eight adaptive mutant clones have been made from the total rna extracted from uninoculated upper leaves of a single cowpea plant exhibiting systemic infection after inoculation with a hybrid cowpea chlorotic mottle bromovirus (ccmv) with the 3a movement protein gene of ccmv replaced by that of cowpea-nonadapted brome mosaic bromovirus (bmv). sequence and mutational analyses of these clones showed genotypic and phenotypic diversity of the cloned virus population, but all examined clones had the a ... | 1999 | 10229274 |
| a brome mosaic virus intergenic rna3 replication signal functions with viral replication protein 1a to dramatically stabilize rna in vivo. | brome mosaic virus (bmv), a positive-strand rna virus in the alphavirus-like superfamily, encodes two rna replication proteins. the 1a protein has putative helicase and rna-capping domains, whereas 2a contains a polymerase-like domain. saccharomyces cerevisiae expressing 1a and 2a is capable of replicating a bmv rna3 template produced by in vivo transcription of a dna copy of rna3. although insufficient for rna3 replication, the expression of 1a protein alone results in a dramatic and specific s ... | 1999 | 10074107 |
| spatial perturbations within an rna promoter specifically recognized by a viral rna-dependent rna polymerase (rdrp) reveal that rdrp can adjust its promoter binding sites. | rna synthesis during viral replication requires specific recognition of rna promoters by the viral rna-dependent rna polymerase (rdrp). four nucleotides (-17, -14, -13, and -11) within the brome mosaic virus (bmv) subgenomic core promoter are required for rna synthesis by the bmv rdrp (r. w. siegel et al., proc. natl. acad. sci. usa 94:11238-11243, 1997). the spatial requirements for these four nucleotides and the initiation (+1) cytidylate were examined in rnas containing nucleotide insertions ... | 1999 | 9847322 |
| functions of the 3'-untranslated regions of positive strand rna viral genomes. | positive strand rna viral genomes are unique in the viral world in serving a dual role as mrna and replicon. since the origin of the minus-strand rna replication intermediate is at the 3'-end of the genome, the 3'-untranslated region (utr) clearly plays a role in viral rna replication. the messenger role of this same rna likely places functional demands on the 3'-utr to serve roles typical of cellular mrnas, including the regulation of rna stability and translation. current understanding indicat ... | 1999 | 11701820 |
| rna sequence and secondary structural determinants in a minimal viral promoter that directs replicase recognition and initiation of genomic plus-strand rna synthesis. | viral rna replication provides a useful system to study the structure and function of rnas and the mechanism of rna synthesis from rna templates. previously we demonstrated that a 27 nt rna from brome mosaic virus (bmv) can direct correct initiation of genomic plus-strand rna synthesis by the bmv replicase. in this study, using biochemical, nuclear magnetic resonance, and thermodynamic analyses, we determined that the secondary structure of this 27 nt rna can be significantly altered and retain ... | 1999 | 10610788 |
| mapping sequences active in homologous rna recombination in brome mosaic virus: prediction of recombination hot spots. | the mechanism of homologous recombination has been studied previously in brome mosaic virus (bmv), a tricomponent, positive-stranded rna virus of plants, by using artificial sequences (reviewed by j. j. bujarskip. d. nagy (1996). semin. virol. 7, 363-372). here we extend these studies over bmv-derived sequences to obtain clues on prediction of homologous recombination hot spots. first, mismatch mutations, which reduced the au content, were introduced into the common 60-nt recombination hot-spot ... | 1999 | 9927577 |
| rna-controlled polymorphism in the in vivo assembly of 180-subunit and 120-subunit virions from a single capsid protein. | repeated, specific interactions between capsid protein (cp) subunits direct virus capsid assembly and exemplify regulated protein-protein interactions. the results presented here reveal a striking in vivo switch in cp assembly. using cryoelectron microscopy, three-dimensional image reconstruction, and molecular modeling, we show that brome mosaic virus (bmv) cp can assemble in vivo two remarkably distinct capsids that selectively package bmv-derived rnas in the absence of bmv rna replication: a ... | 1999 | 10570127 |
| the cognate coat protein is required for cell-to-cell movement of a chimeric brome mosaic virus mediated by the cucumber mosaic virus movement protein. | cucumber mosaic cucumovirus (cmv) and brome mosaic bromovirus (bmv) have many similarities, including the three-dimensional structure of virions, genome organizations, and requirement of the coat protein (cp) for cell-to-cell movement. we have shown that a chimeric bmv with the cmv 3a movement protein (mp) gene instead of its own cannot move from cell to cell in chenopodium quinoa, a common permissive host for both bmv and cmv. another chimeric bmv was constructed by replacing both mp and cp gen ... | 1999 | 10600595 |