| structural aspects of a protein epitope and their role in the major histocompatibility complex control of t cell responsiveness. | we have previously shown that immunization of c57bl/10 (h-2b) mice with the tobacco mosaic virus protein (tmvp) or with its tryptic peptide number 8, representing residues 93-112 of tmvp, induces t cells which proliferate in vitro in response to tmvp and peptide 8. in contrast, immunization of congenic b10.br (h-2k) mice with either tmvp or with peptide 8 induces t cells which respond in vitro to the homologous but not the heterologous antigen. the capacity to exhibit cross-reactivity between tm ... | 1991 | 1703927 |
| structure of viral b-cell epitopes. | four categories of viral epitopes can be distinguished that have been designated cryptotopes, neotopes, metatopes and neutralization epitopes. specific examples of each epitope type are presented and the methods used for locating their positions in viral proteins are described. the epitopes of four well-characterized viruses, namely poliovirus, foot-and-mouth disease virus, influenza virus and tobacco mosaic virus are briefly described. | 1990 | 1714092 |
| alleged common antigenic determinant of tobacco mosaic virus coat protein and the host protein ribulose-1,5-bisphosphate carboxylase is an artifact of indirect elisa and western blotting. | we have reported the detection of an antigenic determinant shared by the tobacco mosaic virus coat protein and the large subunit of ribulose-1,5-bisphosphate carboxylase, a host protein (r.g. dietzgen and m. zaitlin virology 155, 262-266, 1986). this conclusion was questioned by d. zimmermann and m.h.v. van regenmortel (arch. virol. 106, 15-22, 1989). thus we have reinvestigated this unexpected serological cross-reaction in western immunoblotting and indirect elisa. we found that when skimmed mi ... | 1991 | 1714664 |
| antigenic cross-reactivity potential of synthetic peptides immobilized on polyethylene rods. | a number of continuous epitopes of tobacco mosaic virus protein (tmvp) have been defined by the pepscan technique using polyclonal and monoclonal antibodies to tmvp as well as antisera raised against synthetic peptides. in general, the location of continuous epitopes agreed with the results of earlier studies with peptides synthesized by classical methods although there were some notable exceptions. results obtained with the different types of antibodies used in this study indicated that a homol ... | 1991 | 1715031 |
| plasmodesmatal function is probed using transgenic tobacco plants that express a virus movement protein. | a gene encoding a temperature-sensitive mutant (mpp154a) of the 30-kilodalton movement protein (mp) of tobacco mosaic virus (tmv) was transformed into nicotiana tabacum cv xanthi. transgenic plants expressing the mpp154a gene complemented local and systemic movement of an mp-defective mutant of tmv (u3/12mpfs) at the permissive temperature of 24 degrees c but not at 32 degrees c, the nonpermissive temperature. a microinjection procedure was used to investigate the effects of the modified tmv mp ... | 1991 | 1726784 |
| analysis of cis-regulatory elements involved in induction of a tobacco pr-5 gene by virus infection. | cis-regulatory elements involved in tobacco mosaic virus (tmv)-inducible expression were identified in a tobacco pr-5 gene, encoding an acidic thaumatin-like protein. by fusing upstream sequences of the pr-5 gene to the gus reporter gene and analysing transgenic plants containing these fusions for local and systemic induction of gus activity by tmv, it was found that sequences between -1364 and -718 are involved in tmv induction of pr-5 gene expression. | 1992 | 1731969 |
| tobamovirus-plant interactions. | it is clear that the genetic information responsible for the phenomenon we think of as tmv not only consists of the genes carried in the viral genome, but that numerous plant genes are equally important in viral gene functions. these gene products not only allow the virus to replicate, but may effect functions of evolution that determine what the virus is. even the processes of pathogenesis and resistance appear to involve similarly precise plant interactions. the challenge of the future is to i ... | 1992 | 1733093 |
| pathogenesis-related protein 4 is structurally homologous to the carboxy-terminal domains of hevein, win-1 and win-2. | the extracellular, acidic pathogenesis-related protein, pr-4, was purified to homogeneity from leaves of nicotiana tabacum infected with tobacco mosaic virus (tmv) and characterized by partial amino acid sequencing. complementary dna clones encoding pr-4 were isolated using an oligonucleotide probe based on the sequence of one of the peptides. the deduced pr-4 protein sequence was found to be related to a family of proteins including hevein and win-1, which have an amino-terminal lectin domain a ... | 1991 | 1745223 |
| isolation of mutants of arabidopsis thaliana in which accumulation of tobacco mosaic virus coat protein is reduced to low levels. | we have found that arabidopsis thaliana is susceptible to infection with a crucifer strain of tobacco mosaic virus (tmv-cg); the coat protein of tmv-cg accumulated to a high level in uninoculated rosette leaves several days after inoculation. as a first step in the search for host-coded factors that are involved in virus multiplication, we isolated mutants of a. thaliana in which the accumulation of tmv-cg coat protein was reduced to low levels. of 6000 m2 plants descended from ethyl methanesulf ... | 1991 | 1745239 |
| translational efficiency and competitive ability of mrnas with 5'-untranslated alpha beta-leader of potato virus x rna. | the 5'-untranslated leader sequence of potato virus x (pvx) rna (63 nucleotides apart from cap-structure) consists of two sub-sequences referred to as alpha-sequence (41 nucleotides with no g) and beta-sequence (42 nucleotides upstream from the first aug). computer-based folding predictions suggest that the 5'-proximal region of alpha beta-leader is unstructured. the second structural feature of alpha beta-leader is the presence of the sequences apparently complementary to the 3'-terminal region ... | 1991 | 1764504 |
| uag readthrough is not increased in vivo by moloney murine leukemia virus infection. | expression of the pol gene of the murine leukemia viruses is subject to translational control at the uag termination codon of the upstream gene gag. previous experiments have suggested that: i) moloney murine leukemia virus infection induces a trna(gln)iii) in an in vitro system using the tobacco mosaic virus as template, this trna is able to increase readthrough at the uag codon [1]. here we demonstrate that, in vivo, moloney murine leukemia virus infection does not increase translational readt ... | 1991 | 1782222 |
| tobacco and tomato pr proteins homologous to win and pro-hevein lack the "hevein" domain. | clones corresponding to tobacco pathogenesis-related (pr) proteins pr-4 and tomato pr protein p2 were isolated from phage cdna libraries of tobacco infected with tobacco mosaic virus and tomato infected with cladosporium fulvum, respectively. the probe used in these screenings was a polymerase chain reaction product, synthesized on phage dna from the tobacco cdna library, using a synthetic oligonucleotide primer whose sequence corresponded to the partial amino acid sequence available for p2. the ... | 1991 | 1804403 |
| salicylic acid is a systemic signal and an inducer of pathogenesis-related proteins in virus-infected tobacco. | systemic induction of pathogenesis-related (pr) proteins in tobacco, which occurs during the hypersensitive response to tobacco mosaic virus (tmv), may be caused by a minimum 10-fold systemic increase in endogenous levels of salicylic acid (sa). this rise in sa parallels pr-1 protein induction and occurs in tmv-resistant xanthi-nc tobacco carrying the n gene, but not in tmv-susceptible (nn) tobacco. by feeding sa to excised leaves of xanthi-nc (nn) tobacco, we have shown that the observed increa ... | 1991 | 1820820 |
| the tmv movement protein: role of the c-terminal 73 amino acids in subcellular localization and function. | the role of the c-terminal one-third of the tobacco mosaic virus (tmv) 30-kda movement protein (mp) on its subcellular localization and on virus spread was investigated. we have constructed eight cdnas encoding mps with variable size deletions from the c-terminal end. expression of the truncated proteins was verified in recombinant yeast using an antiserum directed to a synthetic peptide corresponding to 21 amino acids near the n-terminal end of the mp. in transgenic tobacco plants, mp from whic ... | 1991 | 1827229 |
| pathogen-induced proteins with inhibitory activity toward phytophthora infestans. | a bioassay using phytophthora infestans was developed to determine whether inhibitory proteins are induced in pathogen-inoculated plants. using this bioassay, ap24, a 24-kilodalton protein causing lysis of sporangia and growth inhibition of p. infestans, was purified from tobacco plants inoculated with tobacco mosaic virus. analysis of the n-terminal amino acid sequence identified ap24 as the thaumatin-like protein osmotin ii. the sequence was also similar to np24, the salt-induced protein from ... | 1991 | 1841721 |
| complete uncoating of the 5' leader sequence of tobacco mosaic virus rna occurs rapidly and is required to initiate cotranslational virus disassembly in vitro. | destabilizing events required for subsequent cotranslational disassembly of tobacco mosaic virus (tmv) particles in vitro were studied. brief treatment of u-32p-labelled tmv (strain vulgare or u2) with 1% sds exposed only 2.5% of the rna (160 5' nucleotides) in a susceptible subpopulation of virions. limited uncoating occurred almost immediately and appeared to be synchronous because the amount of 5' oligonucleotide marker (omega) recovered remained constant throughout a 15 min period in sds. ad ... | 1991 | 1849966 |
| the complete nucleotide sequence of cucumber green mottle mosaic virus (sh strain) genomic rna. | the complete nucleotide sequence of the genomic rna of cucumber green mottle mosaic virus watermelon strain sh (cgmmv-sh) was determined using cloned cdna. this sequence is 6421 nucleotides long containing at least four open reading frames, which correspond to 186k, 129k, 29k and 17.3k proteins. the 17.3k protein is the coat protein. sequence analysis shows that cgmmv-sh is very closely related to another watermelon strain. cgmmv-w, although three amino acid substitutions in the 29k protein were ... | 1991 | 1856687 |
| construction of tobacco mosaic virus subgenomic replicons that are replicated and spread systemically in tobacco plants. | two tobacco mosaic virus (tmv)-derived replicons, created by deletion of most of the 126/183-kda open reading frame (orf), replicated and systemically invaded tobacco plants when supported by wild type tmv. one rna replicon contained an internal direct repeat of 476 nucleotides from the 3' end of the 30-kda orf. although this rna was replicated, most of the progeny were heterogeneous in size and smaller than the original transcript. a second tmv-derived rna replicon, without any internally repea ... | 1991 | 1871972 |
| measurement of affinity of viral monoclonal antibodies by elisa titration of free antibody in equilibrium mixtures. | the binding affinity of a monoclonal antibody (mab) to tobacco mosaic virus (tmv) was determined by measuring, in an enzyme-linked immunosorbent assay, the amount of free antibody present after ultracentrifugation of virus-antibody complexes at equilibrium. in antibody excess, univalent binding of mabs was observed and the affinity constant was k = 3.2 +/- 0.4 10(8) l/mol; in antigen excess, bivalent antibody binding was observed and the antibody avidity was about 15 times higher. in antigen exc ... | 1991 | 1880426 |
| temporal regulation of tobacco mosaic virus-induced phosphorylation of a host encoded protein. | the in vitro and in vivo phosphorylation of a plant encoded protein (p68) associated with dsrna-dependent protein kinase activity was stimulated at specific time intervals following infection by tobacco mosaic virus or electroporation with dsrna. the level of p68 phosphorylation in infected and mock inoculated protoplasts did not differ significantly until 6 hr. post-infection, when the basal level of phosphorylation increased 2-3 fold in infected protoplasts. maximum phosphorylation of p68 occu ... | 1991 | 1883353 |
| post-transcriptional regulation in higher eukaryotes: the role of the reporter gene in controlling expression. | we have investigated whether reporter genes influence cytoplasmic regulation of gene expression in tobacco and chinese hamster ovary (cho) cells. two genes, uida encoding beta-glucuronidase (gus) from escherichia coli and luc, encoding firefly luciferase (luc), were used to analyze the ability of a cap, polyadenylated tail, and the 5'- and 3'-untranslated regions (utr) from tobacco mosaic virus (tmv) to regulate expression. the regulation associated with the 5' cap structure and the tmv 5'-utr, ... | 1991 | 1886610 |
| the atp requirement for initiation of eukaryotic translation varies according to the mrna species. | the requirement for atp for initiation of eukaryotic mrna translation was tested using gel-filtered rabbit reticulocyte lysates incubated with labelled met-trnafmet and exogenous rna templates, and assaying the formation of labelled 80s initiation complexes in the presence of gtp, or labelled 40s initiation complexes in the presence of a non-hydrolysable analogue of gtp. initiation complex formation on globin mrna, or on capped viral rnas such as papaya mosaic virus rna and tobacco mosaic virus ... | 1991 | 1889398 |
| molecular cloning, sequencing and expression in escherichia coli of the odontoglossum ringspot virus coat protein gene. | the sequence of the 3'-terminal 1865 nucleotides of the genome of the tobamovirus odontoglossum ringspot virus (orsv) was determined. this sequence contained two open reading frames (orfs), 912 and 477 nucleotides long. the 912 nucleotide orf has been identified as the cell-to-cell transport protein gene. the 477 nucleotide orf was expressed in escherichia coli, and the product was detected by antibodies specific for the coat protein of orsv. the amino acid sequence of protein encoded by this or ... | 1991 | 1895062 |
| functional analysis of the tobacco mosaic virus trna-like structure in cytoplasmic gene regulation. | the 3'-untranslated region (utr) of tobacco mosaic virus (tmv), which terminates in a trna-like structure, functionally substitutes for a poly(a) tail in both plant and animal cells. the addition of the tmv 3'-utr to chimeric mrna constructs increases their expression up to 100-fold, increasing both translational efficiency and mrna stability. the domain largely responsible for the regulation maps to a 72 base region immediately upstream of the trna-like structure, however, the 3'-terminal, trna ... | 1991 | 1923770 |
| subcellular localization of acidic and basic pr proteins in tobacco mosaic virus-infected tobacco. | infection of samsum nn tobacco with tobacco mosaic virus (tmv) results in the induction of the synthesis of acidic and basic isoforms of many pathogenesis-related (pr) proteins. by immunogold-electromicroscopy we have shown that pr proteins accumulate mainly in cells around the necrotic spots of tmv-induced lesions. the acidic chitinases, beta-(1,3)-glucanases and thaumatin-like proteins were found to accumulate in extracellular "pocket-like" vesicles while the basic chitinases were found in ele ... | 1991 | 1929881 |
| differential induction of acquired resistance and pr gene expression in tobacco by virus infection, ethephon treatment, uv light and wounding. | genes for acidic, extracellular and basic, intracellular pathogenesis-related (pr) proteins of tobacco were studied for their response to tobacco mosaic virus (tmv) infection, ethephon treatment, wounding and uv light. the genes encoding the acidic pr proteins (pr-1, pr-2, pr-3, pr-4 and pr-5) responded similarly to the different forms of stress. they appeared to be highly inducible by tmv, moderately inducible by ethephon treatment and uv light and not inducible by wounding. the genes for the b ... | 1991 | 1932689 |
| pathogenesis-related acidic beta-1,3-glucanase genes of tobacco are regulated by both stress and developmental signals. | three pathogenesis-related (pr) proteins of tobacco are acidic isoforms of beta-1,3-glucanase (pr-2a, -2b, -2c). we have cloned and sequenced a partial cdna clone (lambda fj1) corresponding to one of the pr-2 beta-1,3-glucanases. a small gene family encodes the pr-2 proteins in tobacco, and similar genes are present in a number of plant species. we analyzed the stress and developmental regulation of the tobacco pr-2 beta-1,3-glucanases by using northern and western analyses and a new technique t ... | 1991 | 1932813 |
| expression of the tobacco mosaic virus movement protein using a baculovirus expression vector. | a cdna clone of the tobacco mosaic virus 30k movement protein (mp) gene was constructed and introduced into an autographa californica nuclear polyhedrosis baculovirus expression vector. infection of spodoptera frugiperda cells with the vector resulted in the synthesis of low levels of mp, which was detected by anti-mp serum as two closely related species of mr approximately 34k and a third species of 32k. the authenticity of the recombinant mp was confirmed by comparison of the protein, on the b ... | 1991 | 1940871 |
| [stability to the tobacco mosaic virus in transgenic tobacco plants, producing human alpha-interferon]. | | 1991 | 1954844 |
| trans complementation of virus-encoded replicase components of tobacco mosaic virus. | we examined whether the 130k and 180k proteins of tobacco mosaic virus (tmv), the putative virus-encoded replicase components, produced by a replication-competent tmv mutant could complement a replication-defective mutant in a single cell. the replication-competent mutant (ldcs29) had a deletion in the coat protein gene and the replication-defective mutant (ldr28) had a large deletion in the gene encoding the 130k and 180k proteins. neither the replication of ldr28 nor the production of the coat ... | 1991 | 1962439 |
| rna pseudoknot domain of tobacco mosaic virus can functionally substitute for a poly(a) tail in plant and animal cells. | the genomes of many rna viruses terminate in a tertiary structure similar to the l-conformation of trnas and this structure is recognized by many trna-specific enzymes such as aminoacyl-trna synthetase. virtually the entire 3'-untranslated region (utr) of tobacco mosaic virus (tmv) rna is involved in an extended tertiary structure containing, in addition to a trna-like structure, a pseudoknot domain that lies immediately upstream. although the functions of these structures are not well understoo ... | 1990 | 1976569 |
| altered function of the tobacco mosaic virus movement protein in a hypersensitive host. | the n gene in nicotiana sp. confers hypersensitive resistance to all strains of tobacco mosaic virus (tmv) and limits the rate of virus spread in infected leaves. to examine the role of the movement protein (mp) of tmv in the hypersensitive reaction (hr), transgenic nicotiana tabacum cv. xanthi-nc (genotype nn) plants that express the mp gene were produced and the molecular size exclusion limit of plasmodesmata in leaf mesophyll cells was monitored. at the hr-permissive temperature (24 degrees) ... | 1991 | 1984651 |
| transfer of the movement protein gene between two tobamoviruses: influence on local lesion development. | the effects of transfer of the movement gene between the tobamoviruses tobacco mosaic virus (tmv) and tobacco mild green mosaic virus (tmgmv) were studied. the movement protein (mp) gene of tmgmv was cloned into an infectious cdna of tmv to build the recombinant virus v23. v23, like tmv and tmgmv, caused systemic infection in nicotiana tabacum xanthi. in n. sylvestris v23 and tmv spread systemically although tmgmv produces necrotic local lesions on this host. v23 and tmv cause systemic infection ... | 1991 | 1984654 |
| specific cessation of minus-strand rna accumulation at an early stage of tobacco mosaic virus infection. | the time course of accumulation of viral plus-strand rnas (genomic rna and subgenomic mrna for the coat protein) and minus-strand rna in tobacco protoplasts synchronously infected with tobacco mosaic virus (tmv) rna was examined. in protoplasts infected with the wild-type tmv l rna, the plus and minus strands accumulated differently not only in quantity but also in the outline of kinetics. the time courses of accumulation of the genomic rna and coat protein mrna were similar: they became detecta ... | 1991 | 1987377 |
| vpg-mediated aggregation of potyviral rna. | rna prepared from the potyvirus tobacco vein mottling virus contained aggregates of the 9.5 kb genomic rna with electrophoretic mobilities corresponding to 20 and 41 kb species. similar aggregates were present in preparations of the rnas of two other potyviruses. aggregation occurred during or after purification of the rna by sucrose gradient centrifugation and alcohol precipitation and was dependent upon the presence of a protein apparently bound covalently to a region at or near the 5' terminu ... | 1991 | 1990064 |
| the tobacco mosaic virus 30k movement protein in transgenic tobacco plants is localized to plasmodesmata. | transgenic tobacco plants expressing a gene encoding the tobacco mosaic virus (tmv) movement protein (30k) were studied using immunocytochemical techniques. the movement protein was shown to be localized within or on most of the plasmodesmata observed in the transformed plant. these results are consistent with the idea that the movement protein interacts with the plasmodesmata to facilitate the cell-to-cell spread of tmv. | 1991 | 1990065 |
| in vivo complementation of infectious transcripts from mutant tobacco mosaic virus cdnas in transgenic plants. | a full-length cdna clone of the u1 (common) strain of tobacco mosaic virus (tmv) was constructed, and highly infectious transcripts were produced in vitro using bacteriophage t7 rna polymerase. frameshift mutations designed to cause premature termination of translation were introduced into either the 30-kda movement protein (mp) gene or the coat protein (cp) gene. the mp-frameshift mutant was unable to locally or systemically infect inoculated tobacco plants. however, inoculation of transgenic t ... | 1991 | 1994570 |
| deletion analysis of the 5' untranslated leader sequence of tobacco mosaic virus rna. | to determine the sequences essential for viral multiplication in the 5' untranslated leader sequence of tobacco mosaic virus rna, mutant tmv-l (a tomato strain) rnas which carry several deletions in this 71-nucleotide sequence were constructed by an in vitro transcription system and their multiplication was analyzed by introducing mutant rna into tobacco protoplasts by electroporation. large deletions of the sequence from nucleotides 9 to 47 or 25 to 71 abolished viral multiplication; when about ... | 1991 | 1995954 |
| the signal for a leaky uag stop codon in several plant viruses includes the two downstream codons. | expression of the rna replicase domain of tobacco mosaic virus (tmv) and certain protein-coding regions in other plant viruses, is mediated by translational readthrough of a leaky uag stop codon. it has been proposed that normal tobacco tyrosine trnas are able to read the uag codon of tmv by non-conventional base-pairing but recent findings that stop codons can also be bypassed as a result of extended translocational shifts (trna hopping) have encouraged a re-examination. in light of the alterna ... | 1991 | 2010914 |
| [tobacco mosaic virus: molecular biology and pathology]. | | 1991 | 2017552 |
| tobacco rattle virus rna-1 29k gene product potentiates viral movement and also affects symptom induction in tobacco. | in order to investigate the function of the 29k protein of tobacco rattle virus (trv), we introduced different mutations in the 29k protein gene and analyzed the biological properties of the subsequent transcripts in tobacco plants. although none of the mutant rnas was able to accumulate to a detectable level, the defects in the 29k protein could be complemented by coinoculation with wild-type trv or tobacco mosaic virus (tmv). complementation was also achieved in transgenic plants expressing th ... | 1991 | 2024461 |
| mutation and replacement of the 16-kda protein gene in rna-1 of tobacco rattle virus. | the function of the 16-kda protein encoded by tobacco rattle virus (trv) rna-1 was investigated by a mutational analysis of the 16-kda protein gene. transcripts of trv rna-1 produced from a full-length cdna clone of trv rna-1 (sym strain) remained infectious when the 16-kda protein gene was disrupted by premature termination codons and a deletion which removed 73% of the coding region. a deletion which included the intergenic region between the 29-kda protein gene and the 16-kda protein gene, th ... | 1991 | 2024490 |
| deletion analysis of brome mosaic virus 2a protein: effects on rna replication and systemic spread. | brome mosaic virus (bmv) genomic rna2 encodes the 94-kda 2a protein, which is one of two bmv nonstructural proteins required for rna replication and subgenomic mrna transcription. 2a contains a central polymeraselike region, which has extensive sequence similarity with the sindbis virus nsp4 and tobacco mosaic virus (tmv) 183-kda replication proteins, and also contains n- and c-terminal flanking segments without counterparts in the sindbis virus and tmv nonstructural proteins. to further investi ... | 1991 | 2033655 |
| biological activities of hybrid rnas generated by 3'-end exchanges between tobacco mosaic and brome mosaic viruses. | sequences within the conserved, aminoacylatable 3' noncoding regions of brome mosaic virus (bmv) genomic rnas 1, 2, and 3 direct initiation of negative-strand synthesis by bmv polymerase extracts and, like sequences at the structurally divergent but aminoacylatable 3' end of tobacco mosaic virus (tmv) rna, are required in cis for rna replication in vivo. a series of chimeric rnas in which selected 3' segments were exchanged between the tyrosine-accepting bmv and histidine-accepting tmv rnas were ... | 1991 | 2041076 |
| replication of tmv-l and lta1 rnas and their recombinants in tmv-resistant tm-1 tomato protoplasts. | tm-1 is a gene that provides resistance to tomato plants against tobacco mosaic virus (tmv) infection. in tomato cells carrying the tm-1 gene, multiplication of tmv is inhibited. from previous analysis of resistance-breaking mutants, the involvement of the 130- and 180-kda proteins, putative viral replicases, in the resistance conferred by the tm-1 gene was suggested. when wild-type tmv rna was co-inoculated with a resistance-breaking mutant rna, replication of the wild-type tmv genomic rna coul ... | 1991 | 2053299 |
| interaction of non-enveloped plant viruses and their viral coat proteins with phospholipid vesicles. | the interaction of the non-enveloped plant viruses tmv (rod-shaped) and ccmv (spherical) and of their coat proteins in several well-defined aggregation states, with artificial membranes was investigated to study the early stages of the cellular infection process. information about the separate steps in the interaction mechanisms was obtained by employing three assays, performed as a function of vesicle size, net membrane charge, ph and ionic strength. the assays allow to discriminate between agg ... | 1991 | 2059653 |
| switching in the self-assembly of tobacco mosaic virus. | experimental observations on the structure and physicochemical properties of tmv protein assemblies have led to a fundamental switch in the model of the self-assembly process: rather than being nucleated by the hypothetical two-layer disk, virus assembly appears to be initiated by interaction of the specific rna sequence with a short helical aggregate of the coat protein arranged as in the virus. formation of the 20s nucleating aggregate involves the binding of an average of half a proton per pr ... | 1990 | 2082726 |
| [the construction of a model of the envelope proteins of potex-group viruses]. | amino acid sequences of coat protein of potato x-virus, aucuba potato mosaic, papaya mosaic and white clover mosaic have been comparatively studied. the results of this comparative study have become the basis for prediction of the secondary structure of the viruses and for construction of a model of potexvirus coat protein. the potexvirus coat protein was based on the three-layered arrangement of five alpha spirals. it is supposed that rna molecule is within the protein subunit. availability of ... | 1990 | 2084509 |
| tobacco genes encoding acidic and basic isoforms of pathogenesis-related proteins display different expression patterns. | the induction by cytokinin stress and ethylene of nine different tobacco mosaic virus-inducible mrna classes (termed a-i) encoding pathogenesis-related (pr) proteins was studied. the induced mrna levels were compared to basal levels in healthy tobacco plants grown in tissue culture and in a greenhouse. cytokinin stress and ethylene were found to induce different subsets of the mrnas, indicating that ethylene is not the primary inducing signal in cytokinin-stressed shoots. mrnas f, h and g encodi ... | 1990 | 2101686 |
| the establishment of rat hybridoma cell lines secreting mcab against strains of potato virus y and analysis of its stability. | the rat splenocytes immunized with potato virus y (pvyn) and ratmyeloma (ir983) were fused by peg (m. w.1450). three kinds of stable hybridoma cell lines secreting specific monoclonal antibodies (mcabs) were derived. one kind of the cell lines producing mcabs reacts to pvyn specifically. another reacts to pvyo specifically. the third one reacts to both of the two strains. tested by the methods of sandwich-elisa and indirect-elisa, all kinds of mcabs did not react to seven plant viruses: tobacco ... | 1990 | 2104212 |
| diverse vh and vl genes are used to produce antibodies against a defined protein epitope. | mab secreting hybridomas were produced from mice hyperimmune to the model ag tobacco mosaic virus protein. six mab were selected for their ability to bind synthetic peptides corresponding to amino acid residues 103-112 and 97-107 of tobacco mosaic virus protein. these mab were analyzed for their fine specificity by measuring binding to synthetic analogs of the decapeptide, and cdna sequences encoding the mab v regions were determined. these analyses revealed that a wide range of different v regi ... | 1990 | 2108208 |
| transgenic tobacco plants expressing a coat protein gene of tobacco mosaic virus are resistant to some other tobamoviruses. | transgenic tobacco plants expressing the coat protein (cp) gene of tobacco mosaic virus were tested for resistance against infection by five other tobamoviruses sharing 45-82% homology in cp amino acid sequence with the cp of tobacco mosaic virus. the transgenic plants (cp+) showed significant delays in systemic disease development after inoculation with tomato mosaic virus or tobacco mild green mosaic virus compared to the control (cp-) plants, but showed no resistance against infection by ribg ... | 1990 | 2131095 |
| analysis of acidic and basic chitinases from tobacco and petunia and their constitutive expression in transgenic tobacco. | cdna clones of messenger rnas for acidic and basic chitinases were isolated from libraries of tobacco mosaic virus-infected samsun nn tobacco and petunia. the tobacco cdna clones for acidic chitinase fell into two different groups, whereas all petunia cdna clones had the same sequence. also, tobacco genomic clones were isolated and one was characterized. this genomic clone, corresponding to one of the cdna clones, showed that this acidic chitinase gene contains two introns. the amino acid sequen ... | 1990 | 2131096 |
| characterization of the masked strain of tobacco mosaic virus: identification of the region responsible for symptom attenuation by analysis of an infectious cdna clone. | a strain of tobacco mosaic virus (tmv) that produces mild (attenuated) symptoms on tobacco plants has been molecularly cloned to identify the region of the genome responsible for symptom attenuation. a full-length cdna clone whose transcripts produce the parental disease phenotype on both systemic and hypersensitive host plants has been constructed. this infectious clone was sequenced, and 55 base changes relative to the published sequence of common tmv (strain u1) were identified. these changes ... | 1990 | 2131099 |
| isolation and characterization of a proteinaceous inhibitor of microbial proteinases induced during the hypersensitive reaction of tobacco to tobacco mosaic virus. | a proteinase inhibitor is strongly induced in tobacco leaves reacting hypersensitively to tobacco mosaic virus. the tobacco inhibitor is highly active against four different serine endoproteinases of fungal and bacterial origin (ec 3.4.21.14) but inhibits poorly two serine endoproteinases of animal origin, trypsin (ec 3.4.21.4) and chymotrypsin (ec 3.4.21.1). the inhibitor has been purified to homogeneity by successive steps of conventional and high-performance liquid chromatography. when electr ... | 1990 | 2134857 |
| analysis of stress-induced or salicylic acid-induced expression of the pathogenesis-related 1a protein gene in transgenic tobacco. | the cis-acting elements for regulating gene expression of the tobacco pathogenesis-related 1a protein gene were analyzed in transgenic plants. the 5'-flanking 2.4-kilobase fragment from the pathogenesis-related 1a protein gene was joined to the bacterial beta-glucuronidase gene and introduced into tobacco cells by agrobacterium-mediated gene transfer. promoter activity was monitored by quantitative and histochemical assay of beta-glucuronidase activity in leaves of regenerated transgenic plants. ... | 1990 | 2136635 |
| mechanism of length determination in bacteriophage lambda tails. | the mechanism of length determination in bacteriophage lambda tails is discussed as a model for regulation in protein assembly systems. the lambda tail is a long flexible tube ending in a conical part and a single tail fiber. its length is exactly determined in the sense that the number of major tail protein (gpv) molecules, which comprise more than 80% of the mass of the tail, is exactly the same in all tails. assembly of gpv is regulated by the initiator complex, which contains the tail fiber ... | 1990 | 2150582 |
| analysis of regulatory elements involved in the induction of two tobacco genes by salicylate treatment and virus infection. | tobacco genes encoding the pr-1a protein and a glycine-rich protein are expressed after treatment of plants with salicylate or infection with tobacco mosaic virus. upstream sequences of these genes were fused to reporter genes, and these constructs were used to transform tobacco. upstream sequences of the pr-1a gene of 689 base pairs or longer were sufficient for induction of the reporter gene in tobacco mosaic virus-inoculated leaves, systemically induced leaves from infected plants, and leaves ... | 1990 | 2152122 |
| local and systemic spread of tobacco mosaic virus in transgenic tobacco. | expression of a chimeric gene encoding the coat protein (cp) of tobacco mosaic virus (tmv) in transgenic tobacco plants confers resistance to infection by tmv. we investigated the spread of tmv within the inoculated leaf and throughout the plant following inoculation. plants that expressed the cp gene [cp(+)] and those that did not [cp(-)] accumulated equivalent amounts of virus in the inoculated leaves after inoculation with tmv-rna, but the cp(+) plants showed a delay in the development of sys ... | 1990 | 2152177 |
| capping of tobacco mosaic virus rna. analysis of viral-coded guanylyltransferase-like activity. | the 5' end of tobacco mosaic virus (tmv) genomic rna is capped with 7-methylguanosine. a virus-coded polypeptide with guanylyltransferase activity has been investigated. this enzyme is responsible for forming the 5'----5' linkage of guanosine 5'-monophosphate to the 5'-diphosphate of an acceptor rna, thereby forming the cap. a critical step in the mechanism for cap formation in the eukaryotic nucleus is for guanylyltransferase to bind covalently to guanosine 5'-monophosphate with the hydrolysis ... | 1990 | 2159456 |
| ubiquitinated conjugates are found in preparations of several plant viruses. | recently d.d. dunigan, r.g. dietzgen, j.e. schoelz, and m. zaitlin (virology 165, 310-312, 1988) demonstrated that a small proportion of the subunits of tobacco mosaic virus particles were conjugated with the small protein ubiquitin. we have now detected ubiquitinated conjugates in immunoblots of virion preparations of several other plant viruses, using anti-human ubiquitin antiserum. based on their polyacrylamide gel migrations, plant virus-associated ubiquitin-immunoreactive proteins were cons ... | 1990 | 2162109 |
| translation initiation factor-dependent extracts from saccharomyces cerevisiae. | translation initiation factor 4a- and 4e-dependent extracts were developed from saccharomyces cerevisiae and used to study factor requirements for translation of individual mrnas in vitro. whereas all mrnas tested required eif-4a, mrnas devoid of secondary structure in their 5' untranslated region did not require exogenous eif-4e for translation. the latter included alfalfa mosaic virus rna4, mrna containing the untranslated region of tobacco mosaic virus rna and mrna containing part of the untr ... | 1990 | 2169890 |
| preparation and properties of recombinant dna derived tobacco mosaic virus coat protein. | recombinant dna derived tobacco mosaic virus (vulgare strain) coat protein (r-tmvp) was obtained by cloning and expression in escherichia coli and was purified by column chromatography, self-assembly polymerization, and precipitation. sds-page, amino terminal sequencing, and immunoblotting with polyclonal antibodies raised against tmvp confirmed the identify and purity of the recombinant protein. isoelectric focusing in 8 m urea and fast atom bombardment mass spectrometry demonstrated that the r ... | 1990 | 2198939 |
| the 5'-leader sequence of tobacco mosaic virus rna mediates initiation-factor-4e-independent, but still initiation-factor-4a-dependent translation in yeast extracts. | messenger rnas encoding chloramphenicol acetyltransferase (cat) with or without the 5'-leader sequence of tobacco mosaic virus (tmv) rna were synthesized in vitro and translated in saccharomyces cerevisiae extracts dependent on eukaryotic initiation factors eif-4e or eif-4a. the 5'-leader sequence of tmv rna renders translation of cat mrna eif-4e-independent but still 4a-dependent. | 1990 | 2205536 |
| recognition of the trna-like structure in tobacco mosaic viral rna by atp/ctp:trna nucleotidyltransferases from escherichia coli and saccharomyces cerevisiae. | the 3'-terminal trna-like structure of the tobacco mosaic virus rna interacts with atp/ctp:trna nucleotidyltransferases from escherichia coli or yeast in much the same manner as do trnas. primary sites of interaction cluster near the 3' end and in the loop proposed to be analogous to the psi-loop of a trna. some modified bases in the trna-like structure inhibit interaction with nucleotidyltransferase, yet the analogous bases in a trna do not. the location of some of these nucleotides within the ... | 1990 | 2211637 |
| factors affecting efficient infection of tobacco with in vitro rna transcripts from cloned cdnas of satellite tobacco mosaic virus. | recombinant cdna clones of the complete satellite tobacco mosaic virus (stmv) genome (1059 ribonucleotides) were constructed with unique xbal and hindiii or pstl restriction sites engineered at the 5' and 3' termini, respectively. the genome-length cdnas were positioned downstream of t7 or sp6 phage promoters. genome-sense rnas transcribed in vitro from the t7 promoter were biologically active, while negative-sense rnas transcribed in vitro from the sp6 promoter were not. constructs that were id ... | 1990 | 2219729 |
| sphere-linked immunodiagnostic assay (slida): an electron microscopic method for detecting specific antibodies. | we have developed a sensitive method, sphere-linked immunodiagnostic assay, using specific antigens covalently bonded to microspheres for the detection of antibodies in serum. in this method, specific antigens, such as the capsid proteins of tobacco mosaic virus and tobacco etch virus, were independently, covalently bonded to plastic micropheres of 0.5 microns or 0.9 microns in diameter. the antigen-linked spheres were then exposed to normal serum or serum containing specific antibody, followed ... | 1990 | 2223076 |
| a classification of the tobamoviruses based on comparisons among their 126k proteins. | the products of partial proteolysis of the mr 126,000 in vitro translation products of the rna of eight tobamoviruses were separated by sds-polyacrylamide gel electrophoresis. the peptide patterns obtained were compared using a computer program designed to establish phylogenetic relationships. the resulting most-parsimonious phylogenetic trees grouped the tobamoviruses into clusters i (tobacco mosaic virus, tomato mosaic virus, tobacco mild green mosaic virus, pepper mild mottle virus) and ii (s ... | 1990 | 2230728 |
| tissue-specific expression of the tmv coat protein in transgenic tobacco plants affects the level of coat protein-mediated virus protection. | transgenic tobacco plants were produced that express a chimeric gene encoding the coat protein (cp) of tobacco mosaic virus (tmv) under the control of the promoter from a ribulose bisphosphate carboxylase small subunit (rbcs) gene. plant lines expressing comparable levels of cp from the rbcs and cauliflower mosaic virus 35s promoters were compared for resistance to tmv. in whole plant assays the 35s:cp constructs gave higher resistance than the rbcs:cp constructs. on the other hand, leaf mesophy ... | 1990 | 2238465 |
| inhibition of uncoating of tobacco mosaic virus particles in protoplasts from transgenic tobacco plants that express the viral coat protein gene. | the uncoating of tobacco mosaic virus (tmv) particles in protoplasts isolated from leaves of transgenic tobacco plants that express the tmv coat protein gene was investigated. extracts of these protoplasts collected up to 1 hr after inoculation with tmv contained fewer of the complexes ("striposomes") thought to be involved in cotranslational disassembly of virus particles than did extracts of protoplasts that do not express the viral coat protein gene. these results are consistent with the hypo ... | 1990 | 2238480 |
| complementation of coat protein-defective tmv mutants in transgenic tobacco plants expressing tmv coat protein. | transgenic tobacco plants (nicotiana tabacum cv. xanthi) which express tobacco mosaic virus (tmv) u1 strain coat protein (cp) can complement both the assembly and the long-distance spread of cp-defective (dt1) or coat proteinless (dt1g) mutants of tmv. both mutants arose spontaneously from pm2 and exist only as unencapsidated rna in the inoculated leaves of control tobacco plants, where they are unable to form virus particles or to spread systemically. tmv cp expressed in transgenic tobacco plan ... | 1990 | 2238482 |
| translational efficiency: iridovirus early mrnas outcompete tobacco mosaic virus message in vitro. | infection with the iridovirus, frog virus 3, results in the rapid inhibition of host cell protein synthesis and is correlated with activation of an eif-2 kinase. because phosphorylation of eif-2 inhibits ternary complex formation and thus reduces the overall level of translation, it has been suggested that frog virus 3 messages escaped translational shut-off by outcompeting host messages for the remaining translational capacity of the cell. in this report, we show that frog virus 3 messages were ... | 1990 | 2244916 |
| analysis of gene families encoding acidic and basic beta-1,3-glucanases of tobacco. | healthy tobacco plants accumulate beta-1,3-glucanases (glucan endo-1,3-beta-glucosidase; ec 3.2.1.39) in their roots and in specific parts of the flowers. after infection with tobacco mosaic virus, acidic and basic beta-1,3-glucanases are induced in the inoculated and virus-free leaves of the plant. an analysis of cdna clones demonstrated that at least five genes for acidic beta-1,3-glucanases are induced after tobacco mosaic virus infection. southern blot analysis indicated that the tobacco gen ... | 1990 | 2247445 |
| inhibition of protein synthesis by acetyl-coenzyme a in a cell-free system: possible involvement of protein acetylation in the regulation of translation. | acetyl-coenzyme a (coasac) inhibits the rate of incorporation of amino acid into protein in a cell-free system of mouse liver. the effect is more pronounced when exogenous mrna (tobacco mosaic virus or globin mrna) rather than endogenous messages are used. micromolar concentrations of the cofactor block initiation, while millimolar concentrations cause a more general inhibition of the translation process, that affects, in addition, the elongation step. inclusion of [1-14c]acetyl-coa in a protein ... | 1990 | 2282144 |
| insertion of sequences containing the coat protein subgenomic rna promoter and leader in front of the tobacco mosaic virus 30k orf delays its expression and causes defective cell-to-cell movement. | the regulation of the internal open reading frame (orf) of tobacco mosaic virus (tmv) that encodes the 30k movement protein was examined by constructing mutants in vitro with the putative coat protein subgenomic rna promoter and leader sequences inserted upstream of the 30k orf. a mutant with a 49-nucleotide fragment of the promoter region inserted replicated only transiently before being overtaken by a progeny wild-type virus with the insert deleted. a mutant with a 253-nucleotide promoter regi ... | 1990 | 2294638 |
| changing the start codon context of the 30k gene of tobacco mosaic virus from "weak" to "strong" does not increase expression. | the translation initiation region of the 30k gene of tobacco mosaic virus (tmv) was modified by in vitro mutagenesis to create more optimal start codon contexts. a complicating factor was that modifications in this region also altered the 3' terminus of the 183k orf that overlaps the 30k orf. an insertion of gacucga between nucleotides 4901 and 4902 resulted in a purine (g) in position -3 relative to the aug creating a "stronger" start codon context, but this also changed the last four amino aci ... | 1990 | 2294639 |
| time course of tmv 30k protein accumulation in intact leaves. | the kinetics of accumulation of the 30k and coat proteins of tobacco mosaic virus (tmv) which are expressed via subgenomic mrnas were determined in near-synchronously infected cells of intact tobacco leaves. the 30k protein accumulated to maximal levels during the early stages of the infection as previously reported in tobacco protoplasts. however, in intact leaves, 30k protein accumulated for longer periods and attained higher concentrations than in protoplasts, remaining detectable in all late ... | 1990 | 2294644 |
| isolation of complementary dna clones encoding pathogenesis-related proteins p and q, two acidic chitinases from tobacco. | complementary dna clones encoding two isoforms of the acidic endochitinase (chitinase, ec 3.2.1.14) from tobacco were isolated. comparison of amino acid sequences deduced from the cdna clones and the sequence of peptides derived from purified proteins show that these clones encode the pathogenesis-related proteins pr-p and pr-q. the cdna inserts were not homologous to either the bacterial form of chitinase or the form from cucumber but shared significant homology to the basic form of chitinase f ... | 1990 | 2296608 |
| radial density distribution of chromatin: evidence that chromatin fibers have solid centers. | fiber diameter, radial distribution of density, and radius of gyration were determined from scanning transmission electron microscopy (stem) of unstained, frozen-dried chromatin fibers. chromatin fibers isolated under physiological conditions (ionic strength, 124 mm) from thyone briareus sperm (dna linker length, n = 87 bp) and necturus maculosus erythrocytes (n = 48 bp) were analyzed by objective image-processing techniques. the mean outer diameters were determined to be 38.0 nm (sd = 3.7 nm; s ... | 1990 | 2298806 |
| two antiviral proteins from tobacco: purification and characterization by monoclonal antibodies to human beta-interferon. | polyclonal antibodies to human beta-interferon reacted specifically with two plant proteins (gp22 and gp35) by western blot analysis of crude protein extracts from tobacco leaves infected with tobacco mosaic virus. immunoaffinity chromatography of these extracts on a column of immobilized monoclonal antibodies to human beta-interferon and then reversed-phase hplc yielded gp22 and gp35 in a pure state. both proteins reacted with the schiff reagent and concanavalin a (indicating their glycoprotein ... | 1990 | 2300549 |
| the p30 movement protein of tobacco mosaic virus is a single-strand nucleic acid binding protein. | the p30 protein of tobacco mosaic virus (tmv) is required for cell to cell movement of viral rna, which presumably occurs through plant intercellular connections, the plasmodesmata. the mechanism by which p30 mediates transfer of tmv rna molecules through plasmodesmata channels is unknown. we have identified p30 as an rna and single-stranded (ss) dna binding protein. binding of purified p30 to ss nucleic acids is strong, highly cooperative, and sequence nonspecific with a minimal binding site of ... | 1990 | 2302736 |
| study of tmv assembly with heterologous rna containing the origin-of-assembly sequence. | the assembly of tobacco mosaic virus (tmv) is initiated by a specific reaction between a capsid protein oligomer and an origin-of-assembly region (oas) located 900 nucleotides from the 3' terminus of virion rna. packaging is then completed by rod elongation both in the 5' and 3' directions. the temporal order of the direction of elongation and the characteristics of the reaction were studied by analysis of the in vitro assembly reaction between strain u1 protein oligomers and transcripts contain ... | 1990 | 2305548 |
| association of logistic and poisson models of infection with some physical characteristics of a single component plant virus. | a logistic model was recently formulated to describe the relationship between concentration of a single component plant virus and infections produced by inoculation to a local lesion host. in this paper the logistic is combined with a poisson model. the logistic makes accurate fitting possible for a variety of infection-dilution series; and the poisson acts as a base line, indicating whether lesion numbers are compatible with the hypothesis that random infection of similar infection sites has oc ... | 1990 | 2307717 |
| protection against tobacco mosaic virus infection in transgenic plants requires accumulation of coat protein rather than coat protein rna sequences. | transgenic tobacco plants which express a chimeric gene encoding the tobacco mosaic virus (tmv) coat protein (cp) and the tmv 3' untranslated region are protected against infection by tmv. in this study chimeric genes that encode the sequences representing the tmv cp subgenomic rna, but do not produce protein (because of removal of the initiation codon), and rna that lacks the trna-like sequence of the tmv 3' end were expressed in transgenic plants. only plants that accumulated cp, regardless of ... | 1990 | 2309438 |
| replication, stability, and gene expression of tobacco mosaic virus mutants with a second 30k orf. | a series of tobacco mosaic virus (tmv)-hybrids containing a second 30k open reading frame (orf) inserted into different positions of the genome 3' region were constructed. these insertional mutants were used to evaluate the effects of a modified viral genome organization on replication and gene expression. they were evaluated for stability upon systemic infection and subsequent host passage using rnase protection assays. a mutant with the second 30k orf fused in frame to two-thirds of the coat p ... | 1990 | 2309448 |
| polarity of binding of monoclonal antibodies to tobacco mosaic virus rods and stacked disks. | monoclonal antibodies to tobacco mosaic virus that bind only to one end of the viral rods have been shown to recognize the surface of the protein subunit designated as the bottom, which contains the right radial and left radial alpha-helices. the specificity of the antibody binding was established by immunoelectron microscopy of complexes in which the 5' end of the rna had been exposed at the bottom of the helical virus particle. these antibodies have been shown to bind to both ends of the stack ... | 1990 | 2330673 |
| molecular characterization and biological function of the movement protein of tobacco mosaic virus in transgenic plants. | we previously demonstrated, in transgenic tobacco plants, that the role of the movement protein (mp) of tobacco mosaic virus is to facilitate the cell-to-cell spread of viral progeny during infection. an analysis of different tissues of these transgenic plants indicated that the mp accumulated in leaf, stem, and root tissue. the highest levels were detected in older leaves. the relative levels of mp in leaf tissue from transgenic plants were equivalent to, or higher than, the levels of mp in tob ... | 1990 | 2333282 |
| similarities between putative transport proteins of plant viruses. | the nucleic acids of many plant viruses encode proteins with one or more of the following properties: an mr of approximately 30,000, localization in the cell wall of the infected plant and a demonstrated role in cell-to-cell transport of infection. a progressive alignment strategy, aligning first those sequences known to be similar, and then aligning the resulting groups of sequences, was used to examine further the relatedness of the amino acid sequences of putative transport proteins of caulim ... | 1990 | 2345362 |
| long-distance movement and viral assembly of tobacco mosaic virus mutants. | spreading of tobacco mosaic virus in infected plants is of two modes: cell-to-cell movement (to adjacent cells) and long-distance movement (to distant parts of the plant). viral coat protein has been suggested to be involved in long-distance movement. to analyze the function of coat protein in the movement, we used mutants with modifications in the coat protein gene or in the assembly origin on the genomic rna. a mutant which has the coding region for the c-terminal 5 amino acids of the protein ... | 1990 | 2345957 |
| dynamic mechanism of the self-assembly process of tobacco mosaic virus protein studied by rapid temperature-jump small-angle x-ray scattering using synchrotron radiation. | the self-assembly process of tobacco mosaic virus protein (tmvp) was observed by rapid temperature-jump time-resolved solution x-ray small-angle scattering using synchrotron radiation. the temperature-jump device used for the x-ray measurements is rapid enough to cope with even the fastest-assembling process of tmvp, and accumulates data of reasonable signal-to-noise ratios with a minimum total counting time of 7.5 seconds. the measurements suggested that the 20 s disk of tmvp polymerized to sta ... | 1990 | 2352278 |
| [the suppression of the rna expression of the tobacco mosaic virus in joint translation with the rna of the potato x virus in vitro]. | | 1990 | 2364878 |
| the sieving of rod-shaped viruses during agarose gel electrophoresis. i. comparison with the sieving of spheres. | the sieving of rod-shaped viruses during agarose gel electrophoresis is quantitatively analyzed here with a previously proposed model [g. a. griess et al. (1989) biopolymers, 28, 1475-1484] that has one radius (pe) of the effective pore at each concentration of gel. by use of this model and an internal spherical size standard, a plot of electrophoretic mobility vs agarose percentage is converted to a plot of the radius of the effective sphere (effective radius) vs pe. experimentally, when the co ... | 1990 | 2369633 |
| mutational analysis of the pseudoknot region in the 3' noncoding region of tobacco mosaic virus rna. | the approximately 200-nucleotide-long 3'-terminal noncoding region of tobacco mosaic virus (tmv) rna contains a trna-like structure and, in its immediate upstream region, three consecutive pseudoknots, each of which is composed of two double-helical segments. to elucidate the biological functions of the pseudoknot region, we constructed several deletion mutant tmv-l (a tomato strain) rnas by using an in vitro transcription system and tested their ability to multiply in both tobacco plants and pr ... | 1990 | 2370679 |
| deletion of repeated sequences from tobacco mosaic virus mutants with two coat protein genes. | tobacco mosaic virus (tmv) hybrids were constructed in vitro with an extra coat protein gene (gene order 5'- 126k/183k gene-30k gene-first coat protein gene-subgenomic mrna promoter:second coat protein gene-3'). one coat protein gene was wild type and the other was derived from one of three coat protein mutants that elicit distinctive phenotypic responses. the hybrids contained large sequence repeats (up to 747 nucleotides). rna transcripts of each of seven hybrid constructs initiated infections ... | 1990 | 2371767 |
| the complete nucleotide sequence of the genomic rna of the tobamovirus tobacco mild green mosaic virus. | the complete nucleotide sequence of the genomic rna of the tobamovirus tobacco mild green mosaic virus (tm-gmv) was determined. it shows 64.4% sequence homology with the genomic rna of tobacco mosaic virus (tmv) and 66.0% with that of tomato mosaic virus (tomv). its genomic organization is similar to that of tmv and tomv. the 5' proximal open reading frame (orf) encodes a 126k polypeptide and a 183k readthrough product in which nucleotide-binding and polymerase-sequence motifs are found. the thi ... | 1990 | 2371769 |
| plants transformed with a tobacco mosaic virus nonstructural gene sequence are resistant to the virus. | nicotiana tabacum cv. xanthi nn plants were transformed with nucleotides 3472-4916 of tobacco mosaic virus (tmv) strain u1. this sequence contains all but the three 3 terminal nucleotides of the tmv 54-kda gene, which encodes a putative component of the replicase complex. these plants were resistant to infection when challenged with either tmv u1 virions or tmv u1 rna at concentrations of up to 500 micrograms/ml or 300 micrograms/ml, respectively, the highest concentrations tested. resistance wa ... | 1990 | 2385595 |
| production of enkephalin in tobacco protoplasts using tobacco mosaic virus rna vector. | to examine the validity of the strategy to express a foreign gene as a fusion protein with the coat protein (cp) of tobacco mosaic virus (tmv), we have constructed enk rna by using an in vitro transcription system of tmv rna. enk rna differs from tmv rna only in that enk rna carries an additional sequence coding for leu-enkephalin (tyr-gly-gly-phe-leu) (enk) with a preceding in-frame methionine just before the termination codon of cp gene. in protoplasts inoculated with enk rna, cp + enk fusion ... | 1990 | 2387417 |
| the role of modified purine 64 in initiator/elongator discrimination of trna(imet) from yeast and wheat germ. | the role of 2'-ribosylated adenosine 64 in trna(imet) from yeast in initiation/elongation discrimination was investigated. as measured by in vitro translation in rabbit reticulocyte lysate, the specific removal of the 2'-ribosylphosphate at adenosine 64 via periodate oxidation allows trna(imet) to read internal aug codons of the globine messenger rna. yeast met-trna(imet) lacking the modification of nucleoside 64 forms ternary complexes with gtp and elongation factor tu from escherichia coli. th ... | 1990 | 2395634 |
| antiviral activity of s-adenosylhomocysteine hydrolase inhibitors against plant viruses. | three sah hydrolase inhibitors, (rs)-3-adenin-9-yl-2-hydroxypropanoic acid (isobutyl ester) [(rs)-ahpa]; (rs)-9-(2,3-dihydroxypropyl)adenine [(rs)-dhpa] and the carbocyclic analog of 3-deazaadenosine (c-c3ado) were evaluated for their inhibitory activity against tobacco mosaic virus (tmv) and potato virus x (pvx). using the local lesion assay and elisa, we demonstrated that all three compounds inhibit the replication of tmv and pvx. whereas the three compounds proved about equally active against ... | 1990 | 2396830 |
| orientation effects on the electrophoretic mobility of rod-shaped molecules in free solution. | the effect of molecular orientation on the electrophoretic mobility of rod-shaped polylons as measured by free solution capillary electrophoresis is studied by using the tobacco mosaic virus (tmv) as a model solute. this orientational dependence of molecular mobility is measured by observing the influence of electrical field strength (up to 400 v/cm) on the electrophoretic mobility of tmv. the electrophoretic mobility of tmv increases with increasing field strength. this increase can be quantita ... | 1990 | 2400104 |