Publications

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
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 ...	1997	9281513
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 ...	1997	9300384
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 ...	1997	9311881
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 ...	1997	9343194
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 ...	1996	9258605
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.	1996	8864237
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 ...	1996	8890181
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 ...	1996	8891095
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), ...	1996	8980676
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 ...	1996	8627243
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 ...	1996	8628647
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 ...	1996	8631338
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 ...	1996	8636100
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 ...	1996	8642663
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 ...	1996	8649991
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 ...	1996	8659108
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., ...	1996	8661408
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 ...	1996	8661437
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 ...	1996	8692895
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 ...	1996	8758992
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 ...	1996	8764017
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 ...	1996	8764074
c-myb in smooth muscle cells.	the proto-oncogene c-myb is a cellular homolog of a viral oncogene v-myb found in two independently derived avian acute leukemia viruses: avian myeloblastosis vn-us (amv) and e26 leukemia virus (1). the myb gene is highly conserved in eukaryotes, and it usually consists of 15 exons spanning over 35 kb of genomic dna (1).in humans, c-myb gene locus has been mapped to chromosome 6 (6q22-23) however, myb mrna expressed in thymus contains transcripts originating from chromosome 17 (17q25), suggestin ...	1996	21359720
transgenic plantlets of 'chancellor' grapevine (vitis sp.) from biolistic transformation of embryogenic cell suspensions.	transgenic plantlets of 'chancellor' grapevine (vitis l. complex interspecific hybrid) were produced via biolistic transformation. embryogenic cell suspensions were bombarded with 1 μm tungsten particles coated with pbi426 which encodes a fusion peptide between β-glucuronidase (gus) and neomycin phosphotransferase ii (nptii). the fusion peptide is under the control of a double 35s cauliflower mosaic virus promoter and a leader sequence from alfalfa mosaic virus. the cells were placed on kanamyci ...	1996	24178348
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 ...	1995	8847536
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 ...	1995	8578994
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 ...	1995	8578997
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 ...	1995	8583254
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 ...	1995	8588921
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 ( ...	1995	8722297
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 ...	1995	9049339
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 ...	1995	9049342
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 ...	1995	9345458
antisense 2'-o-alkyl oligoribonucleotides are efficient inhibitors of reverse transcription.	reverse transcription is one step of the retroviral development which can be inhibited by antisense oligonucleotides complementary to the rna template. 2'-o-alkyl oligoribonucleotides are of interest due to their nuclease resistance, and to the high stability of the hybrids they form with rna. oligonucleotides, either fully or partly modified with 2'-o-alkyl residues, were targeted to an rna template to prevent cdna synthesis by the avian myeloblastosis virus reverse transcriptase (amv rt). full ...	1995	7532858
the complete nucleotide sequence of rna 3 of a peach isolate of prunus necrotic ringspot virus.	the complete nucleotide sequence of rna 3 of the pe-5 peach isolate of prunus necrotic ringspot ilarvirus (pnrsv) was obtained from cloned cdna. the rna sequence is 1941 nucleotides and contains two open reading frames (orfs). orf 1 consisted of 284 amino acids with a calculated molecular weight of 31,729 da and orf 2 contained 224 amino acids with a calculated molecular weight of 25,018 da. orf 2 corresponds to the coat protein gene. expression of orf 2 engineered into a ptrchis vector in esche ...	1995	11831718
influenza a virus rna polymerase subunit pb2 is the endonuclease which cleaves host cell mrna and functions only as the trimeric enzyme.	the influenza a virus rna-dependent rna polymerase catalyzes several reactions in transcription and replication of the genome rna. the first step in viral mrna synthesis is the endonucleolytic cleavage of host cell mrnas containing a cap structure to generate capped primers that are 10-14 nucleotides long which are then used to prime transcription of virus-specific mrnas. to analyze the properties of the capped rna-specific endonuclease associated with the influenza virus polymerase and the role ...	1995	11831724
n-terminal basic amino acids of alfalfa mosaic virus coat protein involved in the initiation of infection.	alfalfa mosaic virus coat protein or its messenger rna is required in the inoculum for virus infection. the n-terminus of the coat protein is required for activity; thus, changes were made in the amino acid sequence of this region. six coat protein mutants were tested for activity in virus infection assays in protoplasts. a coat protein mutant in which n-terminal residues 3-19 were absent was inactive; whereas, a mutant in which residues 3-11 were absent (cp deltan9) still had 73% of wild-type a ...	1995	11831728
interaction between rna-dependent rna polymerase of alfalfa mosaic virus and its template: oxidation of vicinal hydroxyl groups blocks in vitro rna synthesis.	in the life cycle of a (+)-strand rna plant virus the processes of template rna recognition and initiation of the synthesis of a complementary strand by the viral rna-dependent rna polymerase (rdrp) are crucial early steps. using a template-dependent in vitro rna synthesizing system of alfalfa mosaic virus (aimv) we were able to study the effect of small chemical modifications of the 3' end of the template rnas on product formation. after oxidation of the 3'-terminal nucleoside of the template n ...	1995	7491788
continuous rt-pcr using amv-rt and taq dna polymerase: characterization and comparison to uncoupled procedures.	a continuous reverse transcription polymerase chain reaction (rt-pcr) procedure was designed with all reaction components included in a single tube prior to thermal cycling. this procedure was compared to uncoupled rt-pcr procedures wherein the addition of reagents was separated. in the latter, in particular, conditions for reverse-primer annealing and cdna synthesis were investigated. the two rt-pcr approaches were compared in the detection of singly spliced and multiply spliced human immunodef ...	1995	7541215
2'-fluoropolynucleotide-directed reverse transcriptase reactions. effect of homologous polynucleotides.	several homologous polynucleotides have been tested as inhibitors on the reactions catalyzed by avian myeloblastosis virus (amv) reverse transcriptase, in the presence of polyribonucleotides and 2'-fluorinated polynucleotides as templates. polynucleotides differentially inhibited the reactions catalyzed by reverse transcriptase in the presence of these synthetic templates. polyriboadenylic acid (poly(ra), poly(2'-o-methyladenylic acid) (poly(am)), poly(2'-fluoro-2'-deoxyadenylic acid) (poly(dafl ...	1995	7542323
high-affinity ssdna inhibitors of the reverse transcriptase of type 1 human immunodeficiency virus.	the reverse transcriptase (rt) of hiv-1 is a plausible target for therapeutic agents aimed at inhibiting propagation of the virus. we have used "irrational drug design", that is, combinatorial chemistry with oligonucleotide libraries, to identify high-affinity ligands aimed at hiv-1 rt. the methodology, termed selex (systematic evolution of ligands by exponential enrichment), was employed with a single-stranded dna library. the selected ssdna ligands bind hiv-1 rt with kd values as low as 1 nm a ...	1995	7542922
reverse transcriptase and substrate dependence of the rna hypermutagenesis reaction.	g-->a hypermutation is a remarkable phenomenon resulting from retroviral reverse transcription in the presence of highly biased dntp concentrations. of the three reverse transcriptases (rtases) available, those of human immunodeficiency virus type 1 (hiv-1), avian myeloblastosis virus (amv) and moloney murine leukemia virus (momlv), the hiv-1 enzyme showed the greatest sensitivity to biased [dctp]/[dttp] ratios. the hiv-1 rtase was able to discriminate between dutp, ditp and the four dna precurs ...	1995	7544458
comparable sensitivities for detection of hiv-1 reverse transcriptase (rt) and other polymerases by rt assays requiring no radioisotopic materials.	an improved non-radioisotopic (non-ri) reverse transcriptase (rt) assay with a template-primer-immobilized microtiter plate is described, which has greater sensitivity than the former non-ri rt assay previously described. non-ri and commercially available non-radioactive (non-ra) rt assays were compared for their ability to detect various polymerases. two rts from rous-associated virus 2 (rav-2) and avian myeloblastosis virus (amv), one polymerase from escherichia coli (pol-i) and one recombinan ...	1995	7545693
rna duplex unwinding activity of alfalfa mosaic virus rna-dependent rna polymerase.	an rna-dependent rna polymerase (rdrp) purified from alfalfa mosaic virus-infected tobacco is capable of synthesizing in vitro full-size rnas of minus and plus polarities. however, the enzyme is not able to perform a complete replication cycle in vitro. the products were found to be completely base-paired to their templates. the enzyme was able to use double-stranded rna as a template for rna synthesis if it could initiate from a single-stranded promoter. the inability (of most) of our enzyme pr ...	1995	7556595
high-affinity rna-binding domains of alfalfa mosaic virus coat protein are not required for coat protein-mediated resistance.	a virus-based vector was used for the transient expression of the alfalfa mosaic virus coat protein (cp) gene in protoplasts and plants. the accumulation of wild-type cp conferred strong protection against subsequent alfalfa mosaic virus infection, enabling the efficacy of cp mutants to be determined without developing transgenic plants. expression of the cp mrna alone without cp accumulation conferred weaker protection against infection. the activity of the n-terminal mutant cps in protection d ...	1995	7568056
characterization of sequences controlling the synthesis of alfalfa mosaic virus subgenomic rna in vivo.	rna 3 of alfalfa mosaic virus encodes the movement protein p3 and the viral coat protein (cp). cp is translated from a subgenomic (sg) messenger, rna 4. to characterize the sg promoter that is responsible for rna 4 synthesis in vivo, putative sg promoter sequences were inserted in a unique xhol site located between the initiation codon of the p3 gene and a second in-frame atg codon in an infectious cdna clone of rna 3. mutants with an active sg promoter insert expressed an n-terminally truncated ...	1995	7571436
mrnas containing the unstructured 5' leader sequence of alfalfa mosaic virus rna 4 translate inefficiently in lysates from poliovirus-infected hela cells.	poliovirus infection is accompanied by translational control that precludes translation of 5'-capped mrnas and facilitates translation of the uncapped poliovirus rna by an internal initiation mechanism. previous reports have suggested that the capped alfalfa mosaic virus coat protein mrna (aimv cp rna), which contains an unstructured 5' leader sequence, is unusual in being functionally active in extracts prepared from poliovirus-infected hela cells (pi-extracts). to identify the cis-acting nucle ...	1995	7609069
the complete nucleotide sequence of apple mosaic virus rna-3.	the complete nucleotide sequence of apple mosaic ilarvirus (apmv) rna-3 has been determined from cloned viral cdnas. the 5' terminus of rna-3 was determined by direct rna sequencing, while the 3' end was determined by polyadenylation of genomic rna and sub-cloning using oligo dt. apmv rna-3 is 2056 bases in length and encodes at least two open reading frames. it is similar in size and genome organization to the rna-3 of other members of the bromoviridae, which includes ilarviruses. the cp gene i ...	1995	7646355
prunus necrotic ringspot ilarvirus: nucleotide sequence of rna3 and the relationship to other ilarviruses based on coat protein comparison.	the rna3 of prunus necrotic ringspot ilarvirus (pnrsv) has been cloned and its entire sequence determined. the rna3 consists of 1943 nucleotides (nt) and possesses two large open reading frames (orfs) separated by an intergenic region of 74 nt. the 5' proximal orf is 855 nt in length and codes for a protein of molecular mass 31.4 kda which has homologies with the putative movement protein of other members of the bromoviridae. the 3' proximal orf of 675 nt is the cistron for the coat protein (cp) ...	1995	7730792
in vitro evidence that the coat protein of alfalfa mosaic virus plays a direct role in the regulation of plus and minus rna synthesis: implications for the life cycle of alfalfa mosaic virus.	the coat protein of alfalfa mosaic virus has both structural and regulating functions. the latter is evident from the fact that the genomic rnas of the virus, although they are of messenger polarity, cannot start an infection cycle in the absence of cost protein. the reason could be that the coat protein is needed for viral rna synthesis. indeed, the coat protein has been found in tight association with the viral rna polymerase (r. quadt et al., 1991, virology 182, 309-315). to investigate the r ...	1995	7747430
ability of tobacco streak virus coat protein to substitute for late functions of alfalfa mosaic virus coat protein.	the coat protein (cp) of tobacco streak virus (tsv) can substitute for the early function of alfalfa mosaic virus (aimv) cp in genome activation. replacement of the cp gene in aimv rna 3 with the tsv cp gene and analysis of the replication of the chimeric rna indicated that the tsv cp could not substitute for the function of aimv cp in asymmetric plus-strand rna accumulation but could encapsidate the chimeric rna and permitted a low level of cell-to-cell transport.	1995	7769722
replicase-mediated resistance to alfalfa mosaic virus.	tobacco plants transformed with the p1 and p2 replicase genes of alfalfa mosaic virus (aimv) have been shown to produce functional replicase proteins, permitting their infection with aimv inocula lacking the genome segments encoding p1 and p2, respectively. to see whether expression of a mutant p2 protein would interfere with the assembly of a functional replicase complex, tobacco plants were transformed with modified p2 genes. when plants were transformed with a p2 gene encoding an n-terminally ...	1995	7886950
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
a chromatographic analysis of capsid protein isolated from alfalfa mosaic virus: zinc binding and proteolysis cause distinct charge heterogeneity.	the capsid protein (cp) of alfalfa mosaic virus (aimv) is required for viral replication when susceptible plants are inoculated with purified viral genomic rna. the discovery of aimv cp in the zinc activated rna-dependent rna polymerase complex prompted our further investigation of aimv virions and the potential involvement of aimv cp in metal binding. aimv cp, isolated from nucleoprotein components, fractionated into four distinct ionic species when purified by cation exchange fast protein liqu ...	1994	7941357
mapping of the rna-binding domain of the alfalfa mosaic virus movement protein.	in-frame contiguous deletions were created in the movement protein gene of alfalfa mosaic virus by site-directed mutagenesis. the mutated movement proteins were expressed in escherichia coli, extracted and then purified by denaturing gel electrophoresis and then renatured. their binding ability with rna was assayed by electrophoretic retardation and u.v.-crosslinking. results indicated that a domain included within amino acids 36 to 81 was necessary for rna binding.	1994	7964629
resistance of green peas to legume viruses.	a total of 16 green pea cultivars (pisum sativum l.) were screened for resistance to bean yellow mosaic virus (bymv), pea enation mosaic virus (pemv), and alfalfa mosaic virus (amv). cvs. avola, midget, wawerplus, wawerex, bunny and banff were found immune to bymv infection. cvs. marx and pion exhibited a high level (above 95%) of resistance to bymv, but they were highly susceptible to pemv and amv. it is recommended to use bymv-immune or highly bymv-resistant cultivars for further breeding. the ...	1994	7976868
early and late functions of alfalfa mosaic virus coat protein can be mutated separately.	to investigate the role of alfalfa mosaic virus coat protein (cp) in genome activation, asymmetric plus-strand rna accumulation, and cell-to-cell spread of the virus, mutations were made in the cp gene and putative cp binding sites in the 3'-untranslated region (utr) of rna 3. mutants that produced no cp-related peptide or cp with an n-terminal deletion of 20 amino acids were defective in all three functions. insertion of several nonviral amino acids at position 85 of cp had little effect on gen ...	1994	8030250
plants transformed with a mutant alfalfa mosaic virus coat protein gene are resistant to the mutant but not to wild-type virus.	transgenic tobacco plants expressing the wild-type (wt) coat protein (cp) gene of alfalfa mosaic virus (aimv) have been shown to be resistant to infection with viral particles and rnas or to infection with viral particles only. the difference in resistance of these plants to rna inocula was found to correlate with a difference in the expression level of the transgene. plants expressing a mutant aimv cp with the n-terminal serine residue changed to glycine have been shown to be susceptible to inf ...	1994	8053151
bean cyclophilin gene expression during plant development and stress conditions.	cyclophilins (cyp) are ubiquitous proteins with peptidyl-prolyl cis-trans isomerase activity that catalyses rotation of x-pro peptide bonds and facilitates the folding of proteins; these enzymes are believed to play a role in in vivo protein folding. during development of normal bean plants, cyp transcripts are first detected three days after beginning of germination and are present in all plant tissues examined. in a general way, higher amounts of cyp mrnas are found in developing tissues. cyp ...	1994	7811975
a coupled one-step reverse transcription pcr procedure for generation of full-length open reading frames.	a one-step (all reactants added simultaneously) reverse transcription and polymerase chain reaction (rt-pcr) procedure for amplification of full-length open reading frames (orfs) of relatively rare transcripts was developed. it was applied for cloning rat luteinizing hormone/chorionic gonadotropin receptor cdna isoforms larger than two kb. in the procedure developed, manual work is minimized, thus large numbers of samples can be handled, since after denaturation of template rna and the primers a ...	1994	7514006
development of an assay that detects transcriptionally competent human immunodeficiency virus type one particles.	to study the functional properties of hiv-1 reverse transcriptase (rt) from intact viral particles without the requirement for tissue culture expansion, a method that couples hiv-1 reverse transcription utilizing its endogenous rt (ert) with polymerase chain reaction amplification (pcr) was developed. detection of endogenous reverse transcripts from hiv particles by ert-pcr was compared to hiv rna pcr detection using avian myeloblastosis virus (amv) rt from plasma samples from 45 hiv-1 infected ...	1994	7519626
quantitative analysis of rna cleavage during rna-directed dna synthesis by human immunodeficiency and avian myeloblastosis virus reverse transcriptases.	we have determined the extent of rna cleavage carried out during dna synthesis by either human immunodeficiency virus (hiv) or avian myeloblastosis virus (amv) reverse transcriptases (rts). conditions were chosen that allowed the analysis of the cleavage and synthesis performed by the rt during one binding event on a given template-primer. the maximum quantity of ribonuclease h (rnase h) sensitive template rna left after synthesis by the rts was determined by treatment with escherichia coli rnas ...	1994	7524028
fidelity of nucleic acid amplification with avian myeloblastosis virus reverse transcriptase and t7 rna polymerase.	the nucleic acid sequence-based amplification (nasba) process involves alternate steps of dna synthesis from an rna template and rna synthesis from a dna template, using avian myeloblastosis virus (amv) reverse transcriptase and t7 rna polymerase, respectively. the overall fidelity of the amplification process was determined by sequence analysis of cloned dna products of nasba reactions. an error frequency of less than 0.3% was observed in cloned dna products from two different segments of the h ...	1994	7532977
alleged reaction in gel-immunodiffusion of an igm monoclonal antibody with alfalfa mosaic virus and cucumber mosaic virus is an artefact.	a previously reported spurious serological cross-reaction between alfalfa mosaic virus (amv) and cucumber mosaic virus (cmv), which had been defined by the reaction in gel-immunodiffusion tests of a single igm monoclonal antibody (mab), mab 8, was no longer detected in the presence of 0.1 m-nacl. the non-specific reactivity of this igm was also confirmed in western blotting assays. when skimmed milk was used as a blocking agent and as a diluent of antibodies, mab 8 failed to recognize amv and cm ...	1994	8113772
nucleotide sequence and structural determinants of specific binding of coat protein or coat protein peptides to the 3' untranslated region of alfalfa mosaic virus rna 4.	the specific binding of alfalfa mosaic virus coat protein to viral rna requires determinants in the 3' untranslated region (utr). coat protein and peptide binding sites in the 3' utr of alfalfa mosaic virus rna 4 have been analyzed by hydroxyl radical footprinting, deletion mapping, and site-directed mutagenesis experiments. the 3' utr has several stable hairpins that are flanked by single-stranded (a/u)ugc sequences. hydroxyl radical footprinting data show that five sites in the 3' utr of alfal ...	1994	8139004
transformation of myelomonocytic cells by the avian myeloblastosis virus is determined by the v-myb oncogene, not by the unique long terminal repeats of the virus.	the avian myeloblastosis virus (amv) induces acute monoblastic leukemia in chickens and transforms only myelomonocytic cells in vitro. the long terminal repeat (ltr) regulatory region of amv is unique among the known classes of avian retrovirus ltrs. we demonstrate that the substitution of the amv ltrs by rous sarcoma virus ltrs did not alter the cell type specificity or the transforming ability of the virus.	1994	8139052
the complete nucleotide sequence of prune dwarf ilarvirus rna 3: implications for coat protein activation of genome replication in ilarviruses.	the complete nucleotide sequence of prune dwarf ilarvirus (pdv) rna 3 has been determined from cloned viral cdnas. the pdv rna 3 is 2129 nucleotides and contains two large open reading frames (orfs) separated by an intergenic region of 72 nucleotides. the 5' proximal orf (orf-1) is 882 nucleotides, encoding a gene product which shares homology with putative cell-to-cell movement proteins of related viruses, including tobacco streak virus (tsv) and alfalfa mosaic virus (aimv). the downstream orf ...	1994	8178476
the 3'-untranslated region of alfalfa mosaic virus rna 3 contains at least two independent binding sites for viral coat protein.	the 3'-termini of the three genomic rnas of alfalfa mosaic virus contain a common sequence of 145 nucleotides (nt) with a specific binding site for coat protein (cp). this sequence consists of several stem/loop structures interspersed with single-stranded augc-motifs; in rna 3 this folding pattern is extended to a region upstream of the homologous sequence. by band-shift assays a minimum of two specific binding sites for cp were identified near the 3'-end of rna 3. site 1 consists of the region ...	1994	8190624
nucleotide sequence of apple mosaic ilarvirus rna 4.	the complete nucleotide sequence of apple mosaic ilavirus rna 4 was obtained from cloned cdnas and direct sequencing of the 5'-terminal rna region. the sequence is 891 nucleotides long and can encode a protein of 226 amino acids (m(r) 25,171) that, by analogy to alfalfa mosaic virus (almv) and tobacco streak virus (tsv), should correspond to the coat protein (cp). database comparisons showed that no significant similarity to other proteins was apparent. analysis of the cp sequence revealed a put ...	1994	8207407
new overlapping gene encoded by the cucumber mosaic virus genome.	cucumber mosaic virus (cmv) contains three genomic rnas (rnas 1, 2, and 3) and a subgenomic rna (rna 4), a shared feature of the bromoviridae family which includes cucumoviruses, bromoviruses, alfalfa mosaic virus, and ilarviruses. we describe in this paper the molecular characterization of a novel subgenomic rna of the q strain of cmv (q-cmv), rna 4a, which was first reported in 1973 (k. w. c. peden and r. h. symons, virology 53, 487-492, 1973). rna 4a is 682 nucleotides and is identical in seq ...	1994	8291242
specific rna binding by amino-terminal peptides of alfalfa mosaic virus coat protein.	specific rna-protein interactions and ribonucleoprotein complexes are essential for many biological processes, but our understanding of how ribonucleoprotein particles form and accomplish their biological functions is rudimentary. this paper describes the interaction of alfalfa mosaic virus (a1mv) coat protein or peptides with viral rna. a1mv coat protein is necessary both for virus particle formation and for the initiation of replication of the three genomic rnas. we have examined protein deter ...	1994	8313916
the 3'-terminal untranslated region of alfalfa mosaic virus rna 4 facilitates the rna entry into translation in a cell-free system.	in order to understand the role of the 3'-terminal untranslated region (3'-utr) of alfalfa mosaic virus (almv) rna 4 in viral rna translation we have constructed the rna derivatives differing in the length of their 3'-terminal portions and expressed them in a wheat germ extract. the result shows that the removal of the 3'-utr from almv rna 4 causes a lagged rna translation in the cell-free system as compared with the translation of the full length rna 4, thus suggesting the involvement of the 3' ...	1993	8325376
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 ...	1993	8336948
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 ...	1993	8343601
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 ...	1993	8372454
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 ...	1993	8389361
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
[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 ...	1993	8394038
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, ...	1993	8411337
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 ...	1993	8437857
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 ...	1993	8464384
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 ...	1993	8464726
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 ...	1993	8478425
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 ...	1993	8503193
characterization of wheat germ protein synthesis initiation factor eif-4c and comparison of eif-4c from wheat germ and rabbit reticulocytes.	eukaryotic protein synthesis initiation factor (eif)-4c was purified from wheat germ and the molecular weight was calculated to be approximately 19,000 by sds-polyacrylamide gel electrophoresis. a similar molecular weight was determined by gel filtration chromatography indicating that wheat germ eif-4c is functional as a single polypeptide chain. an efficient in vitro translation system dependent upon the addition of eif-4c was developed. this system was used to determine the concentrations of e ...	1993	8227048
characterization of the lectin from the bulbs of eranthis hyemalis (winter aconite) as an inhibitor of protein synthesis.	the lectin from eranthis hyemalis has been previously characterized as consisting of two polypeptide chains covalently linked by disulfide bond(s) (cammue, b. p., peeters, b., and peumans, w. j. (1985) biochem. j. 227, 949-955). we have further characterized the biochemical properties of the lectin and demonstrated that it possesses the property of inhibition of protein synthesis using in vitro eukaryotic translation systems. the protein also possesses antiviral activity against the plant virus, ...	1993	8227081
effect of the alfalfa mosaic virus movement protein expressed in transgenic plants on the permeability of plasmodesmata.	symplastic transport of different sized fluorescent probes has been assessed in leaf epidermal cells of transgenic nicotiana plants expressing the movement protein (mp) of alfalfa mosaic virus (amv). in both n. tabacum and n. benthamiana, the size exclusion limit (sel) of plasmodesmata increased from m(r) 1000, which represents the commonly accepted limit, to over 4.4k. however, in control plants, movement of a 3k probe was seen in 11 to 22% of the injections, indicating that plasmodesmata may o ...	1993	8245862
coat protein stimulates replication complexes of alfalfa mosaic virus to produce virion rnas in vitro.	viral replication complexes (rcs) were gradient-purified from cowpea mesophyll protoplasts 21 h after inoculation with alfalfa mosaic virus. these membranous structures incorporate [32p]ump into double- and single-stranded rnas in the absence of added template. when coat protein is added prior to the reaction the incorporation in both rna fractions is stimulated several times. part of the single-stranded product rnas are released from the rcs. the stimulation of incorporation in high molecular m ...	1993	8268261
okazaki fragments, a constant component of avian myeloblastosis virus core-bound 7 s dna.	we have shown that the unusual cscl-buoyant density and velocity sedimentation properties of the isolated host 7 s dna species associated with the core fraction of avian myeloblastosis virus (amv) are made mainly by tight association of rna pieces prevalently joined to the single-stranded portion of this material. it was shown indirectly on sedimentation patterns of [methyl-3h]thymidine and [14c]uridine double-labelled and glyoxylated total amv dna, and directly in phosphorylation experiments wi ...	1993	8184785
avian myeloblastosis virus core-bound 7 s dna, a collection of minute replicative host-cell dna structures.	the early replicative nature of avian myeloblastosis virus core-bound 7 s dna (amv dna), indicated by our preceding findings (ríman et al., 1993), has been confirmed using various experimental approaches. it has been shown by agarose and polyacrylamide gel electrophoresis that this dna represents actually a collection of molecules the size of which is strongly reminiscent of the minute early replicative structures found in dna of sea urchin embryos (baldari et al., 1978). with such a characteris ...	1993	8184786
avian myeloblastosis virus core-bound 7 s dna, highly bent minute structures with sequence-directed curvature.	structural properties and length distribution profile of 7 s avian myeloblastosis virus (amv) dna were studied by means of electron microscopy using two different techniques. this dna represents mostly double strands, the single strands being in minority. we have shown directly that this dna forms a bent structure typical of the majority of molecules. these bends are sensitive to the distamycin treatment which stretches most of the bent molecules. some amount (up to 30%) of circular dna molecule ...	1993	8184787
in vitro translation of fractionated virus-specific rna isolated from plasma of chicken infected by avian myeloblastosis virus. unprocessed and processed myeloblastosis-associated virus env-polypeptide precursors.	the 60 s viral rna complex isolated from leukaemic plasma of chicken infected by avian myeloblastosis virus (amv) was denatured, the poly(a)-rna selected and centrifuged in a linear sucrose density gradient. rna from each fraction was translated in vitro and the products were analyzed by slab polyacrylamide gel electrophoresis (page). unprocessed primary translation product (p64env) of mav env gene from 21 s rna fraction was immunoprecipitated by anti-gp85 serum. if, however, this rna was transl ...	1993	7516622
translation of avian myeloblastosis virus genomic rna in vitro.	defective viral particles (dvp) were isolated from the medium of chicken myeloblasts transformed by avian myeloblastosis virus (amv) in the absence of helper viruses (non-producer myeloblasts). a 60s genomic rna complex of amv was isolated from dvp and translated in vitro. the predominant translation product was the gag polyprotein precursor pr76gag.	1993	8105660
colorimetric reverse transcriptase assay for hiv-1.	a colorimetric assay for reverse transcriptase (rt) of the human immunodeficiency virus type 1 (hiv-1) was developed using a double labelled (biotin and digoxigenin) deoxyuridine triphosphate mixture instead of tritiated thymidine triphosphate. after the rt reaction, the newly polymerized strand from oligodeoxythymidylic acid (oligo-dt) contained both biotin and digoxigenin labels. this nucleotide was bound to streptavidin-magnetic beads by the reaction to biotin. at the detection step, an alkal ...	1993	7679395
inhibition of reverse transcriptase activity by extracts of cultured blue-green algae (cyanophyta).	lipophilic and hydrophilic extracts of over 900 strains of cultured blue-green algae (cyanophyta) were examined in vitro for their ability to inhibit the reverse transcriptases (rt) of avian myeloblastosis virus (amv) and human immunodeficiency virus, type 1 (hiv-1). eighteen (2.0%) aqueous extracts showed activity against amv and hiv rts. the maximal level of rt inhibition achieved by some of the active extracts was equivalent to that measured for 3'-azido-2',3'-di-deoxythymidine (azt) at 668 n ...	1993	7683817
[reverse transcriptase of the human immunodeficiency virus: isolation and substrate specificity].	human immunodeficiency virus (hiv-i) reverse transcriptase was expressed in e. coli and purified to homogeneity (e. coli strain rri (prc-rt, prk 248cits)). we have investigated the substrate properties toward to dna synthesis, catalyzed by this enzyme, of some nucleoside-5'-triphosphate analogues, previously studied in the same reactions, catalyzed by amv and m-mlv reverse transcriptases. we have investigated substrate properties of new analogues of 2',3'-dideoxy-2',3'-didehydro- and 2',3'-dideo ...	1993	7686251
modified nucleoside 5'-triphosphates containing 2',3'-fused three-membered rings as substrates for different dna polymerases.	5'-triphosphates of 1-(2',3'-epithio-2',3'-dideoxy-beta-d- lyxofuranosyl)thymine, 1-(2',3'-epithio-2',3'-dideoxy-beta-d-ribofuranosyl)thymine and 2',3'-lyxoanhydrothymidine have been shown to be termination substrates for human immunodeficiency virus (hiv) and avian myeloblastosis virus (amv) reverse transcriptases as well as dna polymerase i from e. coli and dna polymerase beta from rat liver. at the same time they do not terminate dna synthesis catalysed by dna polymerase epsilon from human pl ...	1993	7687565
rnase h activity of reverse transcriptases on substrates derived from the 5' end of retroviral genome.	rna/dna substrates derived from the 5' ends of human immunodeficiency virus (hiv) and moloney murine leukemia virus (mmulv) genomes were used to study the specificity of the rnase h activities of hiv, amv (avian myeloblastosis virus), and mmulv reverse transcriptases. these substrates were selected because they represent the site for the first template switch during proviral dna synthesis. variability of cleavage was observed depending on the origin of the enzyme as well as the sequence of the r ...	1993	7688365