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c-myb and v-myb are differentially phosphorylated by p42mapk in vitro.the product of the c-myb proto-oncogene is a highly conserved transcription factor that has been shown to function as both a transactivator and repressor. the v-myb oncogenes of e26 leukemia virus and avian myeloblastosis virus (amv) encode proteins truncated at both the amino and carboxy termini, deleting portions of the dna-binding and negative regulatory domains present in c-myb. similar truncations of c-myb alter its function, suggesting that the viral proteins lack important regulatory sequ ...19938336948
differential expression of bean chitinase genes by virus infection, chemical treatment and uv irradiation.three chitinases have been shown previously to be induced upon various stresses of bean leaves. time course studies of mrna accumulation of two of them (p3- and p4-chitinases) have been studied upon virus infection, mercuric chloride treatment and uv irradiation. in alfalfa mosaic virus (almv)-infected plants both mrnas, absent in uninfected bean leaves, become detectable 36 h after inoculation. a maximum level of mrnas is reached 84 h after inoculation and, whereas the amount of p3-ch mrna decr ...19938343601
infection of tobacco with alfalfa mosaic virus cdnas sheds light on the early function of the coat protein.coat protein (cp) is required in the inoculum to initiate infection of plants with the three genomic rnas of alfalfa mosaic virus. inoculation of plants with dna copies of rnas 1, 2, and 3, fused to the 35s promoter, resulted in virus replication but the infection level was increased several-fold by addition of cp to the inoculum. when one of the three cdnas was replaced by its corresponding rna molecule there was no infection unless cp was present in the inoculum. plants transformed with a dna ...19938372454
comparison of the substrate-binding pockets of the rous sarcoma virus and human immunodeficiency virus type 1 proteases.a steady state kinetic analysis of the avian myeloblastosis virus/rous sarcoma virus (amv/rsv) and human immunodeficiency virus type 1 (hiv-1) retroviral proteases (prs) was carried out using a series of 40 peptide substrates that are derivatives of the amv/rsv nucleocapsid-pr cleavage site. these peptides contain single amino acid substitutions in each of the seven positions of the minimum length substrate required by the pr for specific and efficient cleavage. these peptide substrates are dist ...19938389361
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 ...19938389906
[in vitro amplification of genome fragments of the mucosal disease virus (bvd-md) using the pcr method].dna in-vitro amplification when a pcr (polymerase chain reaction) method is used (saiki et al., 1985) provides for a simple technique of marked amplification of a selected dna fragment. the length of a dna amplified fragment is determined by two synthetic primers which spontaneously (at an appropriate temperature) hybridize with the opposite ends of antiparallelly oriented strains of denatured dna. the enzyme taq polymerase completes the synthetisation of new dna strains from the primers. repeti ...19938394038
in vitro expression of the human cytomegalovirus dna polymerase gene: effects of sequence alterations on enzyme activity.genomic dna of the towne strain human cytomegalovirus polymerase (pol) gene (4.4-kb rsrii-ncoi segment of the ecori j fragment) was cloned into plasmids containing either the t3 or the t7 promoter for in vitro transcription-translation studies. the translation efficiency of unmodified pol crna was poor in this system and could not be improved by capping. however, the efficiency could be enhanced by replacing the leader sequence with a 40-bp at-rich sequence derived from an alfalfa mosaic virus, ...19938411337
leukemogenicity of v-myb-transformed monoblasts cells can be modulated by normal bone marrow environment.the avian myeloblastosis virus (amv) causes monoblastic leukemia in the chick. two non-producer clones of amv-transformed monoblasts, bm2/c3a and bm2l/a2b5, have been described (see bottazzi et al., this issue). they differ in their growth requirements and in their ability to induce leukemia when injected into the chick embryo. we first genetically tagged these clones by retroviral infection with a vector expressing the bacterial lacz gene. then, we injected the lacz-positive cells via the chori ...19938437857
determination of target nucleotides involved in 7-methoxy-2-nitro-naphtho[2,1-b]furan (r7000)-dna adduct formation.the characterization of target nucleotides involved in the binding to dna of 7-methoxy-2-nitro-naphtho[2,1-b]furan (r7000), a very potent genotoxic nitrofuran derivative, was investigated. since r7000 undergoes metabolic activation prior to interacting with dna, plasmids containing at-rich and gc-rich sequences were devised and treated by r7000 in bacterial cells presenting nitroreductase activity. the nucleotide modifications to these homogeneous fragments that resulted from r7000 treatment wer ...19938464384
role of the 5' leader sequence of alfalfa mosaic virus rna 3 in replication and translation of the viral rna.rna 3 of alfalfa mosaic virus (aimv) encodes the movement protein p3 and the viral coat protein which is translated from the subgenomic rna 4. the 5'-leader sequences of rna 3 of aimv strains s, a, and y differ in length from 314 to 392 nucleotides and contain a variable number of internal control regions of type 2 (icr2 motifs) each located in a 27 nt repeat. infectious cdna clones were used to exchange the leader sequences of the three strains. this revealed that the leader sequence controls t ...19938464726
in vitro production of enzymatically active myosin heavy chain.in order to initiate studies on the structural and functional relationships of the myosin heavy chain, we constructed a full-length complementary dna encoding the isoform that is found in the fast white muscle of the embryonic chicken. the complementary dna contained 108 basepairs of its 3'-untranslated region and was preceded by a leader sequence derived from the alfalfa mosaic virus. similarly, a complementary dna encoding 963 amino acids which encompass the subfragment-1 of myosin and part of ...19938478425
localization and biochemical characterization of alfalfa mosaic virus replication complexes.replication complexes were isolated from alfalfa mosaic virus-infected tobacco protoplasts. most of the rna-synthesizing activity appears to colocalize with the intact chloroplasts upon sucrose-gradient centrifugation of cellular homogenates. further analysis of these replication complexes showed that the enzyme is strongly associated with the outside of the chloroplasts, the endogenous template being well protected against ribonuclease action. rna polymerase activity is sensitive to protease tr ...19938503193
characterization of the alfalfa mosaic virus strain t6.a strain t6 of alfalfa mosaic virus (almv) was characterized. it was isolated from field grown lucerne. purified virus preparations contained four types of particles, b, m, tb and ta, containing separately encapsidated ssrnas 1 to 4. the strain t6 was able to infect 40 different plant species of 9 families, and to develop a systemic infection in most of them. the symptomatology on bean and the rna mobility of the almv strains t6 and 425 were compared. the classical cross-protection experiments o ...19958578994
primase activities constantly present in avian myeloblastosis virus core isolates: detection and basic characteristics.rna-synthesizing activities (rna-sas) by its nature identical with primase activities (pr-as) were found to be constantly present in avain myeloblastosis virus (amv) core isolates. their endogenous templates are molecules of the virus core-bound host cell dna (amv dna) (ríman and beaudreau, 1970) that have been recently recognized as a collection of still active early replicative structures (ríman et al., 1993b). like the pr-as, the rna-sas are not inhibited by alpha-amanitin nor by aphidicolin ...19958578997
inhibition of poly(2'-fluoro-2'-deoxyadenylic acid)-directed-reverse transcriptase activity.some intercalating and nonintercalating drugs have been tested as inhibitors on the dna synthesis reaction catalyzed by avian myeloblastosis virus (amv) reverse transcriptase, in the presence of polyriboadenylic acid (poly(ra)) and poly(2'-fluoro-2'-deoxyadenylic acid) (poly(dafl)) as templates. in both cases, the inhibition was higher with the intercalating drug ethidium bromide than with the nonintercalating analog tetramethyl ethidium bromide. ethidium bromide inhibited more efficiently the p ...19958583254
secondary structure in the 3' utr of egf and the choice of reverse transcriptases affect the detection of message diversity by rt-pcr.the secondary structure in mrna is essential for many processes, but it can present a technical problem in making full-length cdna with reverse transcriptases. furthermore, different reverse transcriptases have differing abilities to transcribe through regions with secondary structure, which can alter the products obtained by reverse-transcribing rna and then pcr-amplifying the product (rt-pcr). we have been interested in studying the posttranscriptional regulation of epidermal growth factor by ...19958588921
purification, characterization, assembly and crystallization of assembled alfalfa mosaic virus coat protein expressed in escherichia coli.the coast protein of alfalfa mosaic virus (amv) was cloned and expressed in escherichia coli as a fusion protein containing a 37 amino acid extension with a (his)6 region for affinity purification. about half of the expressed recombinant coat protein (rcp) was soluble upon extraction and half was insoluble in inclusion bodies. western blot analysis confirmed the identity of the rcp and protoplast infectivity assays indicated that the rcp was biologically active in an early event of amv infection ...19968627243
fate of direct and inverted repeats in the rna hypermutagenesis reaction.rna hypermutagenesis results from cdna synthesis in the presence of highly biased dntp precursor concentrations and preferentially exploits human immunodeficiency virus type 1 (hiv-1) reverse transcriptase. such reaction conditions slow down dna synthesis, which might be conducive to strand transfer and deletion. this has been investigated. a 6 bp inverted repeat nested between 10 bp repeats was efficiently deleted at dctp concentrations typically used. inter- or intramolecular strand transfer b ...19968628647
comparison of self-sustained sequence-replication reaction systems.the 3sr (self-sustained sequence-replication) reaction is a very efficient method for isothermal amplification of target dna or rna sequences in vitro. this method requires three enzymatic activities: reverse transcriptase, dna-dependent rna polymerase and escherichia coli ribonuclease h. we have modified the original protocol by using human immunodeficiency virus (hiv)-1 reverse transcriptase instead of avian myeloblastosis virus (amv) reverse transcriptase to allow amplification with t7 rna po ...19968631338
comparative studies on the substrate specificity of avian myeloblastosis virus proteinase and lentiviral proteinases.the retroviral proteinase (pr) seems to play crucial roles in the viral life cycle, therefore it is an attractive target for chemotherapy. previously we studied the specificity of human immunodeficiency virus (hiv) type 1 and type 2 as well as equine infectious anemia virus prs using oligopeptide substrates. here a similar approach is used to characterize the specificity of avian myeloblastosis virus (amv) pr and to compare it with those of the previously characterized lentiviral prs. all peptid ...19968636100
influenza a virus rna-dependent rna polymerase: analysis of rna synthesis in vitro.influenza a virus rna-dependent rna polymerase, purified from virion ribonucleoprotein particles and from which endogenous genomic rna (vrna) has been depleted by treatment with micrococcal nuclease, was used to study transcription initiation, elongation, and termination in vitro. templates that contained either minus- or plus-sense influenza virus nucleoprotein minigenes with conserved 5' and 3' termini and the uridylate tract were constructed. the dinucleotide apg and alfalfa mosaic virus rna4 ...19968642663
relationship between plus strand dna synthesis removal of downstream segments of rna by human immunodeficiency virus, murine leukemia virus and avian myeloblastoma virus reverse transcriptases.during retroviral reverse transcription the genomic rna is degraded by the rnase h activity of reverse transcriptase (rt). previous results suggest that after rna-directed dna synthesis, fragments of rna remain annealed to the newly synthesized dna [destefano et al.(1991) j. biol.chem. 266, 7423-7431]. these must be removed to allow synthesis of the second dna strand. we measured the ability of hiv-, amv- and mulv-rt to coordinate dna-dependent dna synthesis and removal of downstream segments of ...19968649991
cis-preferential stimulation of alfalfa mosaic virus rna 3 accumulation by the viral coat protein.rna 3 of alfalfa mosaic virus (aimv) encodes the movement protein p3 and the viral coat protein (cp) which is translated from the subgenomic rna 4. rna 3 is able to replicate in tobacco plants transformed with the aimv replicase genes p1 and p2 (p12 plants). frameshifts or deletions in the p3 gene have little effect on rna 3 accumulation in p12 protoplasts whereas such mutations in the cp gene result in a 100-fold reduction of plus-strand rna 3 accumulation. when p12 protoplasts were inoculated ...19968659108
analysis of cis-acting elements in the 5' leader sequence of alfalfa mosaic virus rna 3.the leader sequence of rna 3 of the leiden isolate of alfalfa mosaic virus strain 425 consists of 345 nucleotides (nt) and contains four putative stem-loop structures each with a motif in the loop that resembles the internal control region 2 (icr2) of trna genes. the sequence of the 5' terminal 112 nt of this leader contains one of these stem-loop structures and is sufficient for a reduced accumulation of rna 3 in protoplasts and a delayed accumulation in plants (e. a. g. van der vossen et al., ...19968661408
the 5' terminal sequence of alfalfa mosaic virus rna 3 is dispensable for replication and contains a determinant for symptom formation.transgenic p12 tobacco plants, transformed with the replicase genes p1 and p2 of alfalfa mosaic virus (aimv), can be infected with rna 3 of the tripartitite aimv genome or with a dna copy of rna 3 fused to the camv 35s promoter and nos terminator. the effect of various modifications on the infectivity of the 35s/cdna 3 construct to p12 plants was studied. when nonviral sequences ranging from 11 to 200 bp were inserted between the 35s promoter and cdna 3, the infection became dependent on additio ...19968661437
a mammalian 2-5a system functions as an antiviral pathway in transgenic plants.resistance to virus infections in higher vertebrates is mediated in part through catalysis of rna decay by the, interferon-regulated 2-5a system. a functional 2-5a system requires two enzymes, a 2-5a synthetase that produces 5'-phosphorylated, 2',5'-linked oligoadenylates (2-5a) in response to double-stranded rna, and the 2-5a-dependent rnase l. we have coexpressed these human enzymes in transgenic tobacco plants by using a single plasmid containing the cdnas for both human rnase l and a low mol ...19968692895
effect of hydrocarbons and crude oil contamination on the sensitivity of french bean to alfalfa mosaic virus.determination of local necrotic lesions on primary leaves infected by alfalfa mosaic virus (amv) revealed that hydrocarbons (hc) contamination of the substrate used for cultivation of french bean (phaseolus vulgaris l., cv. black turtle soup) caused a reduction of bean leaf area and an increase of plant sensitivity to amv infection. on the other hand, superficial contamination of the leaves by crude oil caused an inhibition of lesion formation. changes of sds-polyacrylamide gel electrophoresis ( ...19958722297
structural elements of the 3'-terminal coat protein binding site in alfalfa mosaic virus rnas.the 3'-terminal of the three genomic rnas of alfalfa mosaic virus (aimv) and ilarviruses contain a number of augc-motifs separated by hairpin structures. binding of coat protein (cp) to such elements in the rnas is required to initiate infection of these viruses. determinants for cp binding in the 3'-terminal 39 nucleotides (nt) of aimv rna 3 were analyzed by band-shift assays. from the 5'- to 3'-end this 39 nt sequence contains augc-motif 3, stem-loop structure 2 (stlp2), augc-motif 2, stem-loo ...19968758992
accumulation of alfalfa mosaic virus rnas 1 and 2 requires the encoded proteins in cis.rnas 1 and 2 of the tripartite genome of alfalfa mosaic virus (a1mv) encode the replicase proteins p1 and p2, respectively. p1 expressed in transgenic plants (p1 plants) can be used in trans to support replication of a1mv rnas 2 and 3, and p2 expressed in transgenic plants (p2 plants) can be used in trans to support replication of a1mv rnas 1 and 3. wild-type rna 1 was able to coreplicate with rnas 2 and 3 in p1 plants, but this ability was abolished by frameshifts or deletions in the p1 gene of ...19968764017
faetl motif required for leukemic transformation by v-myb.the nuclear protein v-myb, encoded by the avian myeloblastosis virus (amv), can induce acute monoblastic leukemia in vivo and transform chicken myelomonocytic cells in culture. the n terminus of v-myb functions as the dna-binding domain, and multiple central and c-terminal regions of this protein have been reported to function in transcriptional activation of model reporter genes. we showed previously that a c-terminal domain (amino acids 296 to 371) is required for transcriptional activation an ...19968764074
the nucleotide sequence of citrus leaf rugose virus rna 1.the nucleotide sequence of citrus leaf rugose virus (cilrv) rna 1 consists of 3404 nucleotides and contains one open reading frame (orf) which encodes a putative translation product of 1051 amino acids with a calculated m(r) of 118339. both the nucleotide sequence of cilrv rna 1 and its translated polypeptide share similarities with those of the rna 1 of alfalfa mosaic virus. however, the relationship is not as close as that which exists between the polymerase signatures of the two viruses, whic ...19958847536
specific inhibition of human immunodeficiency virus type 1 reverse transcriptase mediated by soulattrolide, a coumarin isolated from the latex of calophyllum teysmannii.soulattrolide (1), a coumarin isolated from calophyllum teysmannii latex, was found to be a potent inhibitor of hiv-1 reverse transcriptase (rt) with an ic50 of 0.34 microm. inhibition was remarkably specific, with no appreciable activity being observed toward hiv-2 rt, amv rt, rna polymerase, or dna polymerases alpha or beta.19968864237
a plant viral coat protein rna binding consensus sequence contains a crucial arginine.a defining feature of alfalfa mosaic virus (amv) and ilarviruses [type virus: tobacco streak virus (tsv)] is that, in addition to genomic rnas, viral coat protein is required to establish infection in plants. amv and tsv coat proteins, which share little primary amino acid sequence identity, are functionally interchangeable in rna binding and initiation of infection. the lysine-rich amino-terminal rna binding domain of the amv coat protein lacks previously identified rna binding motifs. here, th ...19968890181
alfalfa mosaic virus strains t6 and 425 differ in their capsid protein.capsid proteins (cps) of two strains of alfalfa mosaic virus (aimv)-t6 and 425-were compared using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (sds-page) peptide mapping and two-dimensional page (2d-page). the cps had identical molecular mass but differed in their peptide pattern and charge. the aimv strain t6 was isolated from lucerne in czech republic (gallo, 1977). previously, its morhology, symptomatology and rna electrophoretic mobility were characterized and compared with th ...19968891095
bent pseudoknots and novel rna inhibitors of type 1 human immunodeficiency virus (hiv-1) reverse transcriptase.the reverse transcriptase (rt) of the human immunodeficiency virus (hiv) is a proven target for therapeutic intervention of hiv infections. we have found several new rna inhibitors of hiv-1 rt that differ significantly from the pseudoknot ligands found previously, along with a wide variety of pseudoknot variants. one pseudoknot variant and three novel ligands were studied in more detail. each specifically inhibits dna polymerization by hiv rt (half-maximal inhibition at 0.3 to 20 nm inhibitor), ...19968980676
oncogenic point mutations induce altered conformation, redox sensitivity, and dna binding in the minimal dna binding domain of avian myeloblastosis virus v-myb.c-myb is the founder member of a class of transcription factors with tryptophan-rich repeats responsible for dna binding. activated oncogenic forms of myb are encoded by the avian retroviruses, avian myeloblastosis virus (amv) and e26. amv v-myb encodes a truncated protein with 11 point mutations relative to c-myb. the mutations in the dna binding domain (dbd) were reported to impose distinct phenotypes of differentiation on transformed myeloid cells (introna, m., golay, j., frampton, j., nakano ...19979020167
in vitro genetic selection analysis of alfalfa mosaic virus coat protein binding to 3'-terminal augc repeats in the viral rnas.the coat proteins of alfalfa mosaic virus (amv) and the related ilarviruses bind specifically to the 3' untranslated regions of the viral rnas, which contain conserved repeats of the tetranucleotide sequence augc. the purpose of this study was to develop a more detailed understanding of rna sequence and/or structural determinants required for coat protein binding by characterizing the role of the augc repeats. starting with a complex pool of 39-nucleotide rna molecules containing random substitu ...19979032367
the nucleotide sequence of rna3 and rna4 of olive latent virus 2.olive latent virus 2 (olv2), a virus with particle shapes resembling those of alfalfa mosaic alfamovirus (amv), has four major rna species, two of which (rna3 and rna4) were completely sequenced. rna3 was a bicistronic molecule containing two clear-cut orfs, one of which (orf1) coded for a 36.5 kda polypeptide with conserved motifs of the '30k superfamily' movement proteins and the other (orf2) encoded a 20 kda polypeptide identified as the viral coat protein. rna4, which was a little smaller th ...19959049339
the complete nucleotide sequence of rna 3 of citrus leaf rugose and citrus variegation ilarviruses.complete sequence data for the rna 3 of both citrus leaf rugose (cilrv) and citrus variegation (cvv) ilarviruses have been determined. the rnas are 2289 nt (cilrv) and 2309 nt (cvv) in length and both contain the typical bromoviridae arrangement of two open reading frames (orfs) which, when translated, code for proteins that correspond to the mr 32,000 (32k) putative movement proteins (orf 1) and the coat proteins (orf 2) of the respective viruses. the 3' termini of both viruses can be folded to ...19959049342
functional equivalence of common and unique sequences in the 3' untranslated regions of alfalfa mosaic virus rnas 1, 2, and 3.the 3' untranslated regions (utrs) of alfalfa mosaic virus (amv) rnas 1, 2, and 3 consist of a common 3'-terminal sequence of 145 nucleotides (nt) and upstream sequences of 18 to 34 nt that are unique for each rna. the common sequence can be folded into five stem-loop structures, a to e, despite the occurrence of 22 nt differences between the three rnas in this region. exchange of the common sequences or full-length utrs between the three genomic rnas did not affect the replication of these rnas ...19979094656
identification of a competitive translation determinant in the 3' untranslated region of alfalfa mosaic virus coat protein mrna.we report that the competitive translational activity of alfalfa mosaic virus coat protein mrna (cp rna), a nonadenylated mrna, is determined in part by the 3' untranslated region (utr). competitive translation was characterized both in vitro, with cotranslation assays, and in vivo, with microinjected xenopus laevis oocytes. in wheat germ extracts, coat protein synthesis was constant when a fixed amount of full-length cp rna was cotranslated with increasing concentrations of competitor globin mr ...19979121448
antigens produced in plants by infection with chimeric plant viruses immunize against rabies virus and hiv-1.the coat protein (cp) of alfalfa mosaic virus was used as a carrier molecule to express antigenic peptides from rabies virus and hiv. the antigens were separately cloned into the reading frame of alfalfa mosaic virus cp and placed under the control of the subgenomic promoter of tobacco mosaic virus cp in the 30brz vector. the in vitro transcripts of recombinant virus with sequences encoding the antigenic peptides were synthesized from dna constructs and used to inoculate tobacco plants. the plan ...19979159151
turnip yellow mosaic virus rna-dependent rna polymerase: initiation of minus strand synthesis in vitro.an rna-dependent rna polymerase (rdrp) activity was detergent-solubilized from the chloroplast membranes of chinese cabbage leaves infected with turnip yellow mosaic virus (tymv). the template-dependent, micrococcal nuclease-treated activity synthesized full-length minus strands from tymv rna and 3'-fragments as short as a 28-nucleotide-long rna comprising the amino acid acceptor stem of the 3'-trna-like structure (tls). minus strands were shown to arise by de novo initiation with the insertion ...19979217066
the role of the pseudoknot at the 3' end of turnip yellow mosaic virus rna in minus-strand synthesis by the viral rna-dependent rna polymerase.the trna-like structure at the 3' end of turnip yellow mosaic virus (tymv) rna was studied in order to determine the role of this structure in the initiation of minus-strand synthesis in vitro. deletions in the 5'-to-3' direction up to the pseudoknot structure did not result in a decrease of transcription efficiency. however, transcription efficiency was reduced twofold when a fragment of 21 nucleotides, comprising the 3'-terminal hairpin, was used as a template. trna(phe) from yeast, escherichi ...19979223489
myb-induced transformation.the c-myb protooncogene has been implicated in the development of avian and murine hematopoietic neoplasms of the myeloid and lymphoid lineages. the transcription factor encoded by this gene has a dual function in oncogenesis because it regulates genes that prevent apoptosis and genes involved in cellular proliferation. c-myb has repeatedly been a target of retroviral insertional mutagenesis. the most common mechanism by which retroviruses activate c-myb's oncogenic potential is by providing tra ...19969258605
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 ...19979267012
comparison of the role of 5' terminal sequences of alfalfa mosaic virus rnas 1, 2, and 3 in viral rna replication.the 5' untranslated regions (utrs) of the genomic rnas 1, 2, and 3 of alfalfa mosaic virus (amv) are 100, 54, and 345 nucleotides (nt) long, respectively, and lack extensive sequence similarity to each other. rna 3 encodes the movement protein p3 and the coat protein and can be replicated in transgenic tobacco plants expressing the replicase proteins p1 and p2 (p12 plants). 5' cis-acting sequences involved in rna 3 replication have been shown to be confined to the 5' utr. when the 5' utr of rna ...19979281513
synthesis of full-length potyvirus cdna copies suitable for the analysis of genome polymorphism.new methods facilitating the synthesis and amplification of full-length cdna copies of single-stranded viral rna genomes have been developed. a method is described for the efficient purification of potyviral rna and total rna from infected plants and it is shown that they can serve as templates for the efficient synthesis of a full-length, 10 kb long, genomic cdna. two different reverse transcriptases were used (amv-rt and mmlv-rt); only the first reverse transcriptase produced a good quality, f ...19979300384
the structure of alfalfa mosaic virus capsid protein assembled as a t=1 icosahedral particle at 4.0-a resolution.k. fukuyama, s. s. abdel-meguid, j. e. johnson, and m. g. rossmann (j. mol. biol. 167:873-984, 1983) reported the structure of alfalfa mosaic virus assembled from the capsid protein as a t=1 icosahedral empty particle at 4.5-a resolution. the information contained in the structure included the particle size, protein shell thickness, presence of wide holes at the icosahedral fivefold axes, and a proposal that the capsid protein adopts a beta-barrel structure. in the present work, the x-ray diffra ...19979311881
mutations in coat protein binding sites of alfalfa mosaic virus rna 3 affect subgenomic rna 4 accumulation and encapsidation of viral rnas.the 3'-untranslated regions (3'-utrs) of the three rnas of alfalfa mosaic virus (amv) contain a specific binding site for coat protein (cp) and act as a promoter for minus-strand rna synthesis by the purified amv rna-dependent rna polymerase (rdrp) in an in vitro assay. binding of cp to the viral rnas is required to initiate infection. the sequence of the 3'-terminal 39 nucleotides of amv rna 3 can be folded into two stem-loop structures flanked by three single-stranded augc sequences and repres ...19979343194
is lm7 a new human retrovirus or a mycoplasma virion?a putative retrovirus called lm7 was recently isolated from a patient with ms. this retrovirus was detected in lm7 and lm711 cultured human leptomeningeal cells. in the present work, nucleic acids from lm711 cell culture supernatants were purified and subjected to avian myeloblastosis viral (amv) reverse transcriptase and to random polymerase chain reaction (rpcr) in order to characterize the genomic material of lm7 virions. analysis of reverse transcription products allowed the detection of an ...19959345458
the homeobox gene gbx2, a target of the myb oncogene, mediates autocrine growth and monocyte differentiation.the homeobox gene gbx2 was identified as a target gene of the v-myb oncoprotein encoded by the avian myeloblastosis virus (amv). gbx2 activation by c-myb requires signal transduction emanating from the cell surface while the leukemogenic amv v-myb constitutively induces the gbx2 gene. mutations in the dna binding domain of amv-myb render it independent of signaling events and concomitantly abrogate the collaboration between myb and ccaat enhancer binding proteins (c/ebp), which are involved in g ...19979346236
the 3' untranslated region of alfalfa mosaic virus rna3 contains a core promoter for minus-strand rna synthesis and an enhancer element.the 3' untranslated regions (utrs) of the three genomic rnas of alfalfa mosaic virus consist of a 3' homologous sequence of 145 nt and upstream unique sequences 18-34 nt in length. mutations were made in the 3' utr of a cdna clone of rna3. point mutations in five augc motifs which interfere with specific binding of coat protein to the 3' utr had no effect on template activity of rna3 for minus-strand rna synthesis in vitro by purified viral rna-dependent rna polymerase (rdrp). deletion analysis ...19979367392
expression of the catalytic subunit (ul54) and the accessory protein (ul44) of human cytomegalovirus dna polymerase in a coupled in vitro transcription/translation system.the catalytic subunit (ul54) and accessory protein (ul44) of human cytomegalovirus (hcmv) dna polymerase have been cloned and expressed in an in vitro-coupled transcription/translation reticulocyte lysate system. the influence of the 5'-untranslated region (5'-utr) on the efficiency of expression from the circular plasmids has been investigated. for expression of both ul54 and ul44, a truncated form of the alfalfa mosaic virus (amv) rna4 5'-utr was found to be superior to the full-length amv 5'- ...19979367818
one-tube and one-buffer system of rt-pcr amplification of 1d gene of foot-and-mouth disease virus field isolates.a method of reverse transcription (rt) and polymerase chain reaction (pcr) amplification of 1d (vp1) gene of foot-and-mouth disease (fmd) virus using one reaction mixture containing both avian myeloblastosis virus (amv) reverse transcriptase (rtase) and tfl dna polymerase is described. the procedure was time saving, made use of a single buffer for both rt and subsequent amplification and performed better than the two-step procedure usually conducted with moloney murine leukemia virus (mmlv) rtas ...19979385403
occurrence of nepoviruses in rubus species in the czech republic.the occurrence of arabis mosaic virus (amv), raspberry ringspot virus (rrv), tomato black ring virus (tbrv), strawberry latent ringspot virus (slrv) and cherry leaf roll virus (clrv) in cultivated and wild plants of raspberry and blackberry has been studied in the czech republic in 1993-1996. five hundred and seventy samples were collected at 51 localities and assayed by double antibody sandwich enzyme-linked immunosorbent assay (das-elisa). the results represent the first evidence on the occurr ...19979385408
nucleoprotein complexes harboring an extrachromosomal dna closely related to 7 s dna of avian myeloblastosis virus: physico-chemical properties and representation of nucleic acids.the source of avian myeloblastosis virus (amv) dna, an extrachromosomal small polydisperse dna, present in the material forming the postmicrosomal sediment (poms) of lysed chicken leukemic myeloblasts (chlms) is organized into nucleoprotein (np) complexes containing always rna. this material, radioactively double-labelled for dna and rna, separated in isopycnic sucrose gradients into three poms components (a,b,c) differing from one another in properties of labelling for dna and rna, sucrose dens ...19979391649
activities of a lagging dna strand synthesis of nucleoprotein complexes harboring an extrachromosomal dna closely related to avian myeloblastosis virus core-bound dna.nucleoprotein (np) complexes constituting the material of the postmicrosomal sediment (poms) and its three basic components (a, b, c) (ríman and sulová, 1997a), harboring an extrachromosomal dna closely related to amv dna were found to possess dna- and rna-synthesizing activities (sas) reflecting the ability of this material to be intensely labelled for dna and rna, respectively. the types of these na-sas were compatible with those significant for a lagging dna strand synthesis (lss). the use of ...19979391650
replication of alfalfa mosaic virus rna 3 with movement and coat protein genes replaced by corresponding genes of prunus necrotic ringspot ilarvirus.alfalfa mosaic virus (amv) and prunus necrotic ringspot virus (pnrsv) are tripartite positive-strand rna plant viruses that encode functionally similar translation products. although the two viruses are phylogenetically closely related, they infect a very different range of natural hosts. the coat protein (cp) gene, the movement protein (mp) gene or both genes in amv rna 3 were replaced by the corresponding genes of pnrsv. the chimeric viruses were tested for heterologous encapsidation, replicat ...19979400967
the myb leucine zipper is essential for leukemogenicity of the v-myb protein.the amv v-myb oncoprotein causes oncogenic transformation of myelomonocytic cells in vivo and in vitro. its transforming capacity is strictly dependent upon the n-terminal dna binding domain, the central transactivation region, and on the c-terminal domain containing a putative leucine zipper motif. here we show that the v-mybl3,4a mutant, in which leu325 and leu332 of the leucine zipper have been replaced by alanines, failed to induce leukemia in virus infected chicken. this demonstrates that t ...19979416837
the 5' untranslated region of cucumber mosaic virus rna4 confers highly competitive activity on heterologous luciferase mrna in cell-free translation.the cell-free translation of virion rnas of several tripartite rna viruses has shown that rna4, a subgenomic rna, is more competitive than other virion rnas. recently, the 3' untranslated region (utr) of alfalfa mosaic virus (amv) rna4 was identified to be a competitive determinant. in this study, we observed that the rna4 of cucumber mosaic virus (cmv), another tripartite rna virus, was also found to be a strong competitor in translational competition among cmv virion rnas. to identify the comp ...19989475176
rna quantitative analysis from fixed and paraffin-embedded tissues: membrane hybridization and capillary electrophoresis.fixed and paraffin-embedded tissues from pathology department archives are available for rna expression analysis. we describe a general method for quantitation of specific rna sequence extracted from single 6-8-micron human histological tissue sections cut from paraffin blocks. for each specific mrna, the range of linear relationship between the log of the initial total rna concentration and the log of the specific product after reverse transcription (rt)-pcr must be established. we usually perf ...19989494729
bioluminometric method for real-time detection of reverse transcriptase activity.a simple and sensitive technique for detection of reverse transcriptase (rt) activity in real time has been developed. the technique is based on continuous detection of the inorganic pyrophosphate formed in the rt-catalyzed reaction by a luminometric method. the technique has been used for continuous monitoring of rt-catalyzed dna synthesis on both homo- and heteropolymeric templates. the assay is sensitive and yields linear responses between 1.5-960 mu of avian myeloblastosis virus rt (amv-rt). ...19989494733
functional significance of three basic n-terminal amino acids of alfalfa mosaic virus coat protein.infection of tobacco protoplasts with mutant alfalfa mosaic virus (amv) rnas indicated that three basic amino acids in the n-terminus of amv coat protein are important for the biological activity of the coat protein in the beginning of infection. substitution of alanines for lysines at position 14 or 17 in the coat protein resulted in a 5- or 10-fold reduction in the activity of the protein, respectively. however, substitution of alanine for arginine at position 18 entirely abolished activity. a ...19989501033
viral coat protein peptides with limited sequence homology bind similar domains of alfalfa mosaic virus and tobacco streak virus rnas.an unusual and distinguishing feature of alfalfa mosaic virus (amv) and ilarviruses such as tobacco streak virus (tsv) is that the viral coat protein is required to activate the early stages of viral rna replication, a phenomenon known as genome activation. amv-tsv coat protein homology is limited; however, they are functionally interchangeable in activating virus replication. for example, tsv coat protein will activate amv rna replication and vice versa. although amv and tsv coat proteins have ...19989525649
nitric oxide (no) disrupts specific dna binding of the transcription factor c-myb in vitro.in an attempt to elucidate signal transduction pathways which may modulate dna binding of the transcription factor c-myb, we investigated whether c-myb could be a target for the signaling molecule nitric oxide (no) in vitro. no-generating agents severely inhibited specific dna binding of the c-myb minimal dna-binding domain r2r3. this inhibition was readily reversible upon treatment with excess dtt. a redox-sensitive cysteine (c130) was required for this no sensitivity. moreover, a dna-binding d ...19989541005
regulation of single-strand rna synthesis of alfalfa mosaic virus in non-transgenic cowpea protoplasts by the viral coat protein.we have compared the rna synthesis of alfalfa mosaic virus in complete (by rnas 1, 2 and 3) and incomplete infections (by rnas 1 and 2) of cowpea protoplasts. both viral rna polymerase activity and accumulation of viral rna were measured. by annealing rna in solution with 32p-labelled probes of plus and minus polarity followed by treatment with ribonucleases, we determined viral rnas quantitatively in both single- and double-stranded rna fractions. the accumulation of single-stranded rna of posi ...19989572550
the movement protein and coat protein of alfalfa mosaic virus accumulate in structurally modified plasmodesmata.in systemically infected tissues of nicotiana benthamiana, alfalfa mosaic virus (amv) coat protein (cp) and movement protein (mp) are detected in plasmodesmata in a layer of three to four cells at the progressing front of infection. besides the presence of these viral proteins, the plasmodesmata are structurally modified in that the desmotubule is absent and the diameter has increased drastically (almost twofold) when compared to plasmodesmata in uninfected cells or cells in which amv infection ...19989601503
rna determinants of a specific rna-coat protein peptide interaction in alfalfa mosaic virus: conservation of homologous features in ilarvirus rnas.alfalfa mosaic virus (amv) coat protein and tobacco streak virus (tsv) coat protein bind specifically to the 3' untranslated regions of the viral rnas and are required with the genomic rnas to initiate virus replication. a combination of nucleotide substitutions, hydroxyl radical footprinting, and ethylation and chemical modification interference analysis has been used to define the rna determinants important for the specific binding of the 3'-terminal 39 nucleotides of amv rna 3/4 (amv843-881) ...19989614941
cell-to-cell movement of beet necrotic yellow vein virus: i. heterologous complementation experiments provide evidence for specific interactions among the triple gene block proteins.cell-to-cell movement of beet necrotic yellow vein virus (bnyvv) requires three proteins encoded by a triple gene block (tgb) on viral rna 2. a bnyvv rna 3-derived replicon was used to express movement proteins to functionally substitute for the bnyvv tgb proteins was tested by coinoculation of tgb-defective bnyvv with the various replicons to chenopodium quinoa. trans-heterocomplementation was successful with the movement protein (p30) of tobacco mosaic virus but not with the tubule-forming mov ...19989650295
the complete nucleotide sequence of prune dwarf ilarvirus rna-1.the sequence of prune dwarf ilarvirus (pdv) rna-1 has been determined; it consists of 3,374 nucleotides and contains a single open reading frame of 3,168 nucleotides. the putative translation product is 1,055 amino acids in length with a calculated molecular mass of 118.9 kda. both the nucleic acid and the translated amino acid sequences show stronger homology to the corresponding rna-1 and orf-1 of apple mosaic ilarvirus and alfalfa mosaic alfamovirus than to spinach latent mosaic ilarvirus or ...19979672650
the sequence of rna 1 and rna 2 of tobacco streak virus: additional evidence for the inclusion of alfalfa mosaic virus in the genus ilarvirus.here we describe the complete sequence of rna 1 and 2 of the wc isolate of tobacco streak virus (tsv). these two sequences complete the information on the genome of tsv, the type member of the genus ilarvirus, and are the first sequences described for the rna 1 and rna 2 of a member of subgroup 1 of this genus. the sequences have a similar organization to those reported for the corresponding rnas of other ilarviruses. however, the putative translation products of these two molecules differ suffi ...19989687875
comparison of three rna amplification methods as sources of dna for sequencing.dna products generated from a region of the measles virus genome by three rna reverse transcription and amplification methods were cloned and sequenced, and the results were compared in order to evaluate the methods' relative fidelities. the methods were: (i) reverse transcription followed by a nested polymerase chain reaction (rt-npcr), (ii) a combined rt-pcr using rtth polymerase and (iii) nucleic acid sequence-based amplification (nasba). nasba was followed by rt-pcr with rtth polymerase or r ...19989821583
amino acids of alfalfa mosaic virus coat protein that direct formation of unusually long virus particles.in contrast to most alfalfa mosaic virus (amv) strains (ysmv, s, m and 425), amv strains vru and 1 5/64 can form abnormally long virus particles, an ability which has been linked to the coat protein (cp). in order to study this phenomenon, the cp-encoding rnas 3 of amv strains vru and 1 5/64 were cloned and fully sequenced. comparative sequence analyses of amv rna 3 sequences derived from different strains revealed two non-conservative amino acid substitutions, ser65 and leu175, which occur excl ...19989880033
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 ...19989926399
cis-acting functions of alfalfa mosaic virus proteins involved in replication and encapsidation of viral rna.cdna clones of rnas 1 and 2 of alfalfa mosaic virus (amv) were slightly modified to permit transcription of infectious rnas with t7 rna polymerase. together with transcripts of an available clone of amv rna 3, these transcripts were used to study cis- and trans-acting functions of amv proteins in protoplasts from nontransgenic tobacco plants and from plants transformed with the p1 and p2 genes, encoded by rnas 1 and 2, respectively. transgenic p1 was unable to complement mutations in the p1 gene ...19999986798
dna synthesis exhibited by the reverse transcriptase of mouse mammary tumor virus: processivity and fidelity of misinsertion and mispair extension.we have recently expressed in bacteria an enzymatically active reverse transcriptase (rt) of mouse mammary tumor virus (mmtv), a mammalian retrovirus with a typical b-type morphology [taube, r., loya, s., avidan, o., perach, m. & hizi, a. (1998) biochemical j. 329, 579-587]. the purified recombinant protein was shown to possess the catalytic activities characteristic of retroviral reverse transcriptases. in the present study, we have analyzed two basic parameters characteristic of the dna polyme ...19989990322
expression of alfalfa mosaic virus coat protein in tobacco mosaic virus (tmv) deficient in the production of its native coat protein supports long-distance movement of a chimeric tmv.alfalfa mosaic virus (almv) coat protein is involved in systemic infection of host plants, and a specific mutation in this gene prevents the virus from moving into the upper uninoculated leaves. the coat protein also is required for different viral functions during early and late infection. to study the role of the coat protein in long-distance movement of almv independent of other vital functions during virus infection, we cloned the gene encoding the coat protein of almv into a tobacco mosaic ...199910051680
alfalfa mosaic virus rnas serve as cap donors for tomato spotted wilt virus transcription during coinfection of nicotiana benthamiana.tomato spotted wilt virus (tswv) was shown to use alfalfa mosaic virus (amv) rnas as cap donors in vivo during a mixed infection in nicotiana benthamiana. by use of nested reverse transcription-pcr, tswv n and nss mrnas provided with capped leader sequences derived from all four amv rnas could be cloned and sequenced. the sequence specificity of the putative tswv endonuclease involved is discussed.199910233983
alfalfa mosaic virus and ilarviruses: involvement of coat protein in multiple steps of the replication cycle. 199910355754
transformation by v-myb.the v-myb oncogene of the avian myeloblastosis virus (amv) is unique among known oncogenes in that it causes only acute leukemia in animals and transforms only hematopoietic cells in culture. amv was discovered in the 1930s as a virus that caused a disease in chickens that is similar to acute myelogenous leukemia in humans (hall et al., 1941). this avian retrovirus played an important role in the history of cancer research for two reasons. first, amv was used to demonstrate that all oncogenic vi ...199910378700
scope for using plant viruses to present epitopes from animal pathogens.epitope presentation to the immune system for vaccination purposes can be achieved either via an inactivated or attenuated form of a pathogen or via its isolated antigenic sequences. when free, these peptides can adopt a variety of conformations, most of which will not exist in their native environment. conjugation to carrier proteins restricts mobility of the peptides and increases their immunogenicity. a high local concentration of epitopes boosts the immune response further and can be generat ...199810398492
effect of c-terminal mutations of alfalfa mosaic virus coat protein on dimer formation and assembly in vitro.the coat protein (cp) of alfalfa mosaic virus (amv) strain 425 assembles to bacilliform or rod-shaped particles in the presence of nucleic acids or to t = 1 empty icosahedral particles in the absence of nucleic acids. to study the determinants of cp assembly, recombinant cps (rcps) that contained a (his)(6) region were expressed in escherichia coli. wt rcp and a mutant rcp, which lacked the last nine amino acids of the c terminus (amino acids 213-221), assembled to particles that were identical ...199910405370
genome activation in alfamo- and ilarviruses.alfamo- and ilarviruses are characterized by the deficiency of their genomes (three messenger-sense rnas) to start an infection cycle. the rnas are in capsids built from a single species of protein of about 24 kd. a few dimers of this coat protein per rna molecule are sufficient to activate the genome. since the first description of genome activation [bol jf, van vloten-doting l, jaspars emj (1971) virology 46: 73-85] three models have been proposed concerning its mechanism: the protection, the ...199910416370
a conformational switch at the 3' end of a plant virus rna regulates viral replication.3' untranslated regions of alfamo- and ilar-virus rnas fold into a series of stem-loop structures to which the coat protein binds with high affinity. this binding plays a role in initiation of infection ('genome activation') and has been thought to substitute for a trna-like structure that is found at the 3' termini of related plant viruses. we propose the existence of an alternative conformation of the 3' ends of alfamo- and ilar-virus rnas, including a pseudoknot. based on (i) phylogenetic com ...199910469663
in vitro transcription by the turnip yellow mosaic virus rna polymerase: a comparison with the alfalfa mosaic virus and brome mosaic virus replicases.recently, we showed that the main determinant in the trna-like structure of turnip yellow mosaic virus rna to initiate minus-strand synthesis in vitro is the 3' acca end. by mutational analysis of the 3'-terminal hairpin, we show here that only a non-base-paired acca end is functional and that the stability of the wild-type 3'-proximal hairpin is the most favorable, in that it has the lowest deltag value and a high transcription efficiency. with a nested set of rna fragments, we show that the mi ...200010590114
high temperature cdna synthesis by amv reverse transcriptase improves the specificity of pcr.the enzyme avian myeloblastosis virus reverse transcriptase (amv-rt) is routinely used for cdna synthesis, which is generally carried out at temperatures between 37 degrees c and 42 degrees c. we show that this enzyme can support cdna synthesis, at temperatures as high as 70 degrees c. we have utilized this property of the amv-rt to improve the specificity of polymerase chain reaction (pcr). furthermore, this apparently thermophilic property of the enzyme, which is an important constituent of a ...199910631680
the complete nucleotide sequence of apple mosaic virus (apmv) rna 1 and rna 2: apmv is more closely related to alfalfa mosaic virus than to other ilarviruses.the complete nucleotide sequences of apple mosaic virus rna 1 and 2 have been characterized. apple mosaic virus rna 1 is 3476 nucleotides in length and encodes a single large open reading frame (orf), whereas apple mosaic virus rna 2 is 2979 nucleotides in length and also encodes a single orf. the amino acid sequences encoded by rna 1 and 2 show similarity to all of the other ilarviruses for which sequence data are available, but both are more closely related to alfalfa mosaic virus (amv) than t ...200010640567
activation of the alfalfa mosaic virus genome by viral coat protein in non-transgenic plants and protoplasts. the protection model biochemically tested.in non-transgenic host plants and protoplasts alfalfa mosaic virus displays a strong need for coat protein when starting an infection cycle. the "protection model" states that the three viral rnas must have a few coat protein subunits at their 3' termini in order to protect them in the host cell against degradation by 3'- to- 5' exoribonucleases [neeleman l, van der vossen eag, bol jf (1993) virology 196: 883-887]. we demonstrated that the naked genome rnas are slightly infectious, if the inocul ...200010664403
the "small" polydisperse cytoplasmic extrachromosomal dna of chicken leukaemic myeloblasts and the avian myeloblastosis virus core-bound dna seem to descend from origin regions of chromosomal dna replication.nucleotide sequences are presented for 12, 7 and 12 cloned extrachromosomal dnas by nature harbored in nucleoprotein (np) complexes forming chicken leukaemic myeloblast (chlm) post microsomal sediment (poms) components a, b and c, respectively, and for 11 cloned avian myeloblastosis virus (amv) dnas. analysis of the abundance of sequence motifs significant for eukaryotic chromosomal dna replication origin (ori) regions (and their initiation zones) has shown that these dnas are reminiscent of cel ...199910672338
genetic dissection of the multiple functions of alfalfa mosaic virus coat protein in viral rna replication, encapsidation, and movement.coat protein (cp) of alfalfa mosaic virus (amv) binds as a dimer to the 3' termini of the three genomic rnas and is required for initiation of infection, asymmetric plus-strand rna accumulation, virion formation, and spread of the virus in plants. a mutational analysis of the multiple functions of amv cp was made. mutations that interfered with cp dimer formation in the two-hybrid system had little effect on the initiation of infection or plus-strand rna accumulation but interfered with virion f ...200010683324
detection and sequencing of measles virus from peripheral mononuclear cells from patients with inflammatory bowel disease and autism.it has been reported that measles virus may be present in the intestine of patients with crohn's disease. additionally, a new syndrome has been reported in children with autism who exhibited developmental regression and gastrointestinal symptoms (autistic enterocolitis), in some cases soon after mmr vaccine. it is not known whether the virus, if confirmed to be present in these patients, derives from either wild strains or vaccine strains. in order to characterize the strains that may be present ...200010759242
protection of avian myeloblastosis virus (amv) dna polymerase by substrates against heat inactivation. 197410793699
a conserved hairpin structure in alfamovirus and bromovirus subgenomic promoters is required for efficient rna synthesis in vitro.the coat protein gene in rna 3 of alfalfa mosaic virus (amv; genus alfamovirus, family bromoviridae) is translated from the subgenomic rna 4. analysis of the subgenomic promoter (sgp) in minus-strand rna 3 showed that a sequence of 37 nt upstream of the rna 4 start site (nt +1) was sufficient for full sgp activity in an in vitro assay with the purified viral rna-dependent rna-polymerase (rdrp). the sequence of nt -6 to -29 could be folded into a potential hairpin structure with a loop represente ...200010836792
cowpea mosaic virus infection induces a massive proliferation of endoplasmic reticulum but not golgi membranes and is dependent on de novo membrane synthesis.replication of cowpea mosaic virus (cpmv) is associated with small membranous vesicles that are induced upon infection. the effect of cpmv replication on the morphology and distribution of the endomembrane system in living plant cells was studied by expressing green fluorescent protein (gfp) targeted to the endoplasmic reticulum (er) and the golgi membranes. cpmv infection was found to induce an extensive proliferation of the er, whereas the distribution and morphology of the golgi stacks remain ...200010864669
avian retrovirus dna internal attachment site requirements for full-site integration in vitro.concerted integration of retrovirus dna termini into the host chromosome in vivo requires specific interactions between the cis-acting attachment (att) sites at the viral termini and the viral integrase (in) in trans. in this study, reconstruction experiments with purified avian myeloblastosis virus (amv) in and retrovirus-like donor substrates containing wild-type and mutant termini were performed to map the internal att dna sequence requirements for concerted integration, here termed full-site ...200010954527
human respiratory syncytial virus vaccine antigen produced in plants.human respiratory syncytial virus (rsv) is the primary cause of respiratory infection in infants worldwide. currently there is no available vaccine, although studies in animal models have demonstrated protective immunity induced by an epitope of the rsv g-protein representing amino acids 174-187. two peptides containing amino acids 174-187 of the g-protein of the human rsv a2 strain (nf1-rsv/172-187 and nf2-rsv/170-191) were separately engineered as translational fusions with the alfalfa mosaic ...200011053254
tax oncoprotein trans-represses endogenous b-myb promoter activity in human t cells.the b-myb gene was identified on the basis of its homology with the protooncogene c-myb, homolog of the avian myeloblastosis virus (amv) and avian leukemia virus (e26) transforming genes. several studies using antisense constructs or antisense oligonucleotides as well as overexpression experiments suggest that b-myb plays an important role in the transition from g(1) to s phase of the cell cycle and that b-myb expression is cell cycle regulated. we have previously demonstrated that the human t c ...200011080802
rnas 1 and 2 of alfalfa mosaic virus, expressed in transgenic plants, start to replicate only after infection of the plants with rna 3.rnas 1 and 2 of the tripartite genome of alfalfa mosaic virus (amv) encode the two viral replicase subunits. full-length dna copies of rnas 1 and 2 were used to transform tobacco plants (r12 lines). none of the transgenic lines showed resistance to amv infection. in healthy r12 plants, the transcripts of the viral cdnas were copied by the transgenic viral replicase into minus-strand rnas but subsequent steps in replication were blocked. when the r12 plants were inoculated with amv rna 3, this bl ...200111125154
determining 'threshold' levels for seed-borne virus infection in seed stocks.there have been many advances in testing procedures to detect seed-borne virus infection in seed samples. however, scant attention has been given to the implications of improved test results in terms of the economic losses resulting from sowing seed stocks with different amounts of infection. for agricultural and horticultural industries to use the results of tests on representative samples, defined 'threshold' values for percentage seed infection are required that identify acceptable levels of ...200011137171
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