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McLain L, Porta C, Lomonossoff GP, Durrani Z, Dimmock NJ. Human immunodeficiency virus type 1-neutralizing antibodies raised to a glycoprotein 41 peptide expressed on the surface of a plant virus. AIDS Res Hum Retroviruses 1995; 11:327-34. [PMID: 7786579 DOI: 10.1089/aid.1995.11.327] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
An oligonucleotide encoding the amino acids 731-752 of the gp41 envelope protein of the human immunodeficiency virus type 1 strain IIIB, which is known to induce cross-reactive neutralizing antibodies in humans, was inserted into a full-length clone of the RNA encoding the coat proteins of cowpea mosaic virus (RNA 2 of CPMV). When transfected together with RNA 1 of CPMV, transcribed RNA 2 was able to replicate in plants and form infectious virions (CPMV-HIV). Purified virions were injected subcutaneously with alum adjuvant into adult C57/BL6 mice to determine their ability to stimulate ELISA and neutralizing antibody specific for HIV-1. Antisera to CPMV-HIV obtained after only two injections gave a strong ELISA response (mean of 1:25,800) using the free gp41 peptide as antigen, showing that the gp41 peptide incorporated into the chimera was immunogenic. The same antisera gave 97% neutralization of HIV-1 IIIB at 1:100 dilution, with a highly uniform response in all (six of six) animals tested. A third injection barely increased the neutralization titer. Normal mouse serum had no neutralizing activity. Antisera also strongly neutralized the HIV-1 strains RF and SF2. ELISA and neutralizing activity to HIV-1 IIIB declined after the second injection and were undetectable after 7 weeks, but were restimulated to the same level after the third injection. Neutralization was marginally more stable after the third injection. Antibody specific for CPMV epitopes was equally short lived. A bonus of this system was unexpected neutralizing activity specifically stimulated by unmodified CPMV virions, although this amounted to no more than 10% of the neutralizing activity stimulated by the CPMV-HIV chimera.(ABSTRACT TRUNCATED AT 250 WORDS)
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Lomonossoff GP. Pathogen-derived resistance to plant viruses. ANNUAL REVIEW OF PHYTOPATHOLOGY 1995; 33:323-343. [PMID: 18999964 DOI: 10.1146/annurev.py.33.090195.001543] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Porta C, Spall VE, Loveland J, Johnson JE, Barker PJ, Lomonossoff GP. Development of cowpea mosaic virus as a high-yielding system for the presentation of foreign peptides. Virology 1994; 202:949-55. [PMID: 8030255 DOI: 10.1006/viro.1994.1417] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
It has recently been shown that cowpea plants can be infected with a cowpea mosaic virus (CPMV) chimera containing an antigenic site from foot-and-mouth disease virus (Usha et al., Virology 197, 366-374, 1993). Analysis of progeny RNA produced during such an infection has revealed that the inserted sequence is rapidly lost during serial passaging, probably by a process of homologous recombination. Using the information gained from this analysis, we have redesigned the chimeras in such a way that they are now genetically stable. The modified constructs have been used to obtain large quantities of purified virus particles expressing epitopes derived from human rhinovirus 14 (HRV-14) and human immunodeficiency virus type 1 (HIV-1). The chimeric virus particles possess the antigenic properties of the inserted sequence and, in the case of the HRV-14-derived construct, it has been shown that the inserted epitope is immunogenic in rabbits. These results demonstrate that CPMV can be used as a high-yielding system for the presentation of foreign peptide sequences.
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Usha R, Rohll JB, Spall VE, Shanks M, Maule AJ, Johnson JE, Lomonossoff GP. Expression of an animal virus antigenic site on the surface of a plant virus particle. Virology 1993; 197:366-74. [PMID: 7692669 DOI: 10.1006/viro.1993.1598] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To investigate if cowpea mosaic virus (CPMV) particles can be used to express foreign protein sequences, oligonucleotides encoding an epitope derived from VP1 of foot-and-mouth disease virus (FMDV) were cloned into the region of the CPMV genome encoding the small (S) coat protein. The chimeras were designed so that the foreign sequence was expressed either as an insertion or as a replacement for part of the wild-type sequence. While RNA from both chimeras was able to replicate in cowpea protoplasts only the construct containing the FMDV sequence as an insertion was able to direct capsid formation and infect whole cowpea plants. The modified S protein produced in plants infected with the insertion derivative reacted with FMDV-specific antiserum. These results show that CPMV can be used as an antigen presentation system and raises the possibility of producing vaccines in plants using a RNA virus-based vector.
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MESH Headings
- Amino Acid Sequence
- Antigens, Viral/biosynthesis
- Aphthovirus/genetics
- Aphthovirus/metabolism
- Base Sequence
- Blotting, Northern
- Capsid/biosynthesis
- Capsid/chemistry
- Capsid/genetics
- Comovirus/genetics
- Comovirus/metabolism
- Epitopes/biosynthesis
- Gene Expression
- Genome, Viral
- Microscopy, Immunoelectron
- Models, Structural
- Molecular Sequence Data
- Mutagenesis, Insertional
- Plants/microbiology
- Plasmids
- Protein Structure, Secondary
- Protoplasts
- RNA, Viral/genetics
- RNA, Viral/isolation & purification
- Recombinant Fusion Proteins/biosynthesis
- Restriction Mapping
- Transcription, Genetic
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Dessens JT, Lomonossoff GP. Cauliflower mosaic virus 35S promoter-controlled DNA copies of cowpea mosaic virus RNAs are infectious on plants. J Gen Virol 1993; 74 ( Pt 5):889-92. [PMID: 8492093 DOI: 10.1099/0022-1317-74-5-889] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Clones have been constructed that contain full-length cDNA copies of cowpea mosaic virus RNA1 and RNA2, downstream of the cauliflower mosaic virus 35S promoter. The clones, when linearized downstream of the viral sequences, give rise to cowpea mosaic virus-like symptoms when inoculated onto cowpea plants. Viral RNA and virions can be detected in the inoculated plants, demonstrating that the clones are directly infectious.
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31
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Rohll JB, Holness CL, Lomonossoff GP, Maule AJ. 3'-terminal nucleotide sequences important for the accumulation of cowpea mosaic virus M-RNA. Virology 1993; 193:672-9. [PMID: 8460480 DOI: 10.1006/viro.1993.1175] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The location of nucleotide sequences important in determining the extent of cowpea mosaic virus M-RNA accumulation in cowpea protoplasts has been analyzed by deletion mutagenesis of full-length cDNA clones from which infectious transcripts can be produced in vitro. The results suggest that cis-acting sequences which direct replication of M-RNA by B-RNA-encoded products are located within the 5'-terminal 524 nucleotides and the 3'-terminal 151 nucleotides. RNA secondary structure predictions for the 3'-terminal 151 nucleotides of both genomic RNAs (Eggen et al. (1989) Virology 173, 456-464) indicate that the terminal nucleotides form a stable secondary structure composed of a Y-shaped stem-loop and a simple A-U-rich stem-loop. The latter structure has been implicated in B-RNA replication. We have examined the role of the Y-shaped structure in M-RNA accumulation by site-directed mutagenesis of putative base-pairing combinations in the two minor stems. The results suggest that efficient replication is dependent on the formation of both of these minor stem structures.
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32
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Goulden MG, Davies JW, Wood KR, Lomonossoff GP. Structure of tobraviral particles: a model suggested from sequence conservation in tobraviral and tobamoviral coat proteins. J Mol Biol 1992; 227:1-8. [PMID: 1522581 DOI: 10.1016/0022-2836(92)90676-b] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Comparisons of the coat protein sequences of four tobraviruses with those of seven tobamoviruses indicate that these proteins share a common evolutionary origin. Numerous amino acids for which specific functions have been identified in the molecular structure of the tobacco mosaic virus vulgare protein have identical or closely similar counterparts among the tobraviral proteins. These include those with roles in the hydrophobic core of the protein, those that contribute to the RNA binding site and those involved in the control of virus assembly. We suggest a model for the structure of the tobraviral particle that not only offers an explanation for the greater diameter of the tobraviral particle but also confirms an early suggestion for RNA placement within this particle.
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33
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Shanks M, Lomonossoff GP. The nucleotide sequence of red clover mottle virus bottom component RNA. J Gen Virol 1992; 73 ( Pt 9):2473-7. [PMID: 1402822 DOI: 10.1099/0022-1317-73-9-2473] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The complete nucleotide sequence of the bottom component RNA (B RNA) of red clover mottle virus strain S has been determined. The sequence consists of 6033 nucleotides and contains a single long open reading frame sufficient to encode a protein of M(r) 210,258. The proteolytic processing sites within this protein have been deduced by comparison of its sequence with that of the B RNA-encoded protein of cowpea mosaic virus. Comparison of the amino acid sequences of the individual proteins confirms that the two viruses have a similar genome organization.
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Carr JP, Marsh LE, Lomonossoff GP, Sekiya ME, Zaitlin M. Resistance to tobacco mosaic virus induced by the 54-kDa gene sequence requires expression of the 54-kDa protein. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 1992; 5:397-404. [PMID: 1282044 DOI: 10.1094/mpmi-5-397] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Tobacco plants transformed with the sequence encoding the 54-kDa putative replicase protein of tobacco mosaic virus were resistant to systemic virus disease (D. B. Golemboski, G. P. Lomonossoff, and M. Zaitlin, Proc. Natl. Acad. Sci. USA 87:6311-6315, 1990). Resistance was due to a marked suppression of virus replication at the site of inoculation (J. P. Carr and M. Zaitlin, Mol. Plant-Microbe Interact. 4:579-585, 1991). Although RNA transcripts encoding the 54-kDa protein were present in resistant plants, the 54-kDa protein itself was not observed in vivo. We wished to assess the relative importance of the 54-kDa protein versus its RNA in mediating resistance. Further attempts to detect the 54-kDa protein in plant tissues were unsuccessful; therefore, an indirect approach was taken using a protoplast-based transient gene expression system. Electroporation of protoplasts with plasmids capable of expressing the wild-type 54-kDa protein gene sequence or a mutant lacking the first AUG initiation codon of the 54-kDa open reading frame and encoding a slightly truncated protein reduced virus replication in protoplasts. In contrast, a frameshift mutant that was capable of directing synthesis of a protein only 20% the size of the 54-kDa protein, did not produce resistance in protoplasts. These results show that expression of the 54-kDa protein gene sequence at the RNA level alone is insufficient for resistance, and they implicate the 54-kDa protein itself in mediating this resistance phenomenon.
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35
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Oxelfelt P, Shanks M, Widmark AK, Lomonossoff GP. Identification and characterization of pseudo-recombinants of red clover mottle comovirus. J Gen Virol 1992; 73 ( Pt 8):2121-4. [PMID: 1645149 DOI: 10.1099/0022-1317-73-8-2121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
cDNA clones specific for the two genomic RNAs of strain O of the comovirus red clover mottle virus (RCMV) were constructed. Using these clones, in conjunction with clones specific for RNAs of RCMV strain S, local lesion isolates containing reciprocal pseudo-recombinants between strains S and O were identified. Investigation of the biological properties of these pseudo-recombinants showed that the ability of RCMV to infect Chenopodium quinoa is determined by B RNA. The results also suggest that both RNAs are involved in symptom formation in Pisum sativum. Analysis of the strain O clones enabled the sequences at the 3' ends of both genomic RNAs of strain O to be determined. Comparison of these sequences with the corresponding region of the strain S RNAs suggests that the 3' terminal sequences critical for replicase recognition may lie somewhat upstream of the poly(A) tract.
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36
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Dessens JT, Lomonossoff GP. Sequence upstream of the 24K protease enhances cleavage of the cowpea mosaic virus B RNA-encoded polyprotein at the junction between the 24K and 87K proteins. Virology 1992; 189:225-32. [PMID: 1604812 DOI: 10.1016/0042-6822(92)90698-o] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To investigate cleavage at the junction between the cowpea mosaic virus (CPMV) 24K and 87K proteins, plasmids were constructed containing the sequence of bottom-component (B) RNA encoding the 110K protein plus a variable length of upstream coding sequence. Transcripts derived from these clones were translated in rabbit reticulocyte lysate and the appearance of the 87K protein was used to assess the efficiency of cleavage at the 24K-87K junction. The results show that the 110K protein, containing the contiguous sequence of the 24K and 87K proteins, is stable and that efficient cleavage at 24K-87K junction requires the presence of amino acids upstream of the 24K protease. These observations show that the 170K protein rather than the 110K protein is the precursor of the 87K protein and suggest a mechanism whereby both the B RNA-encoded 110K and 87K proteins can accumulate during infection.
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37
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Nida DL, Anjos JR, Lomonossoff GP, Ghabrial SA. Expression of cowpea mosaic virus coat protein precursor in transgenic tobacco plants. J Gen Virol 1992; 73 ( Pt 1):157-63. [PMID: 1730936 DOI: 10.1099/0022-1317-73-1-157] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Tobacco, Nicotiana tabacum L., supports cowpea mosaic virus (CPMV) replication and cell-to-cell movement, and thus may serve as a model system to study coat protein-mediated protection against CPMV. A chimeric gene consisting of the cauliflower mosaic virus 35S promoter, CPMV 60K coat proteins-precursor (CP-P) coding region, and the nopaline synthase polyadenylation signal was transferred to tobacco cv. Burley 21 via the Agrobacterium tumefaciens binary vector system. Gene integration and expression in the transgenic tobacco plants were confirmed by Southern and RNA dot blot analyses. Accumulation of CPMV 60K CP-P in transgenic plants, up to 2 micrograms/g of wet weight tissue, was detected by ELISA and Western blots. The results of Western blots and immunosorbent electron microscopy further indicated that CPMV CP-P neither undergoes autoproteolysis to generate the mature viral coat proteins nor assembles into virus-like capsids, suggesting that processing of the CP-P may be required for virus assembly. Because CPMV neither induces symptoms in tobacco nor moves systemically, evaluation of the reactions of the transgenic plants to virus inoculation was based on virus accumulation in the inoculated leaves. Results from such infectivity experiments did not differentiate between CP-P expressers and vector-transformed plants. The transgenic tobacco plants expressing CP-P should provide valuable material for investigating comovirus polyprotein processing and capsid assembly in vivo.
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38
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Belsham GJ, Lomonossoff GP. The mechanism of translation of cowpea mosaic virus middle component RNA: no evidence for internal initiation from experiments in an animal cell transient expression system. J Gen Virol 1991; 72 ( Pt 12):3109-13. [PMID: 1765773 DOI: 10.1099/0022-1317-72-12-3109] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The possibility that internal initiation of translation is responsible for the synthesis of the middle component (M) RNA-encoded 95K protein of cowpea mosaic virus (CPMV) has been investigated by constructing plasmids in which the entire sequence of CPMV M RNA was cloned downstream of a chloramphenicol acetyltransferase gene. Expression of these plasmids in an animal cell expression system revealed that no synthesis of the proteins encoded by the downstream CPMV open reading frame takes place from RNA derived from these constructs under conditions where the internal ribosome entry site of foot-and-mouth disease virus is functional. The results indicate that internal initiation is not responsible for the synthesis of the 95K protein in this system.
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39
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Dessens JT, Lomonossoff GP. Mutational analysis of the putative catalytic triad of the cowpea mosaic virus 24K protease. Virology 1991; 184:738-46. [PMID: 1887592 DOI: 10.1016/0042-6822(91)90444-g] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To investigate the mechanism of action of the cowpea mosaic virus (CPMV) 24K protease, a full-length cDNA clone of bottom component (B) RNA has been constructed from which RNA can be transcribed in vitro using T7 RNA polymerase. Translation of the resulting RNA in rabbit reticulocyte lysate leads to the synthesis of a 200 kDa product (the 200K protein) which cleaves itself in a manner identical to that of the product translated from B RNA isolated from virions. Site-directed mutagenesis of the full-length clone was used to examine the effects of altering individual amino acids in the 24K protease on its activity. The results obtained are consistent with the prediction that the 24K protease is structurally similar to the trypsin-like family of serine proteases and suggest that His40, Glu76, and Cys166 comprise the active site. Substitution of Cys166 by a serine residue results in an enzyme with reduced catalytic activity.
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40
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MacFarlane SA, Shanks M, Davies JW, Zlotnick A, Lomonossoff GP. Analysis of the nucleotide sequence of bean pod mottle virus middle component RNA. Virology 1991; 183:405-9. [PMID: 2053290 DOI: 10.1016/0042-6822(91)90155-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The complete nucleotide sequence of the middle component RNA (M RNA) of the comovirus bean pod mottle virus (BPMV) has been determined. The sequence consists of 3662 nucleotides and contains a single long open reading frame sufficient to code for a protein of 113,353 Da. The proteolytic processing sites within this protein have been identified by comparison with the known three-dimensional structure of the virion and cleavage at these sites would lead to a range of products consistent with those observed during processing of the M RNA-encoded polyproteins in vitro. We have performed computer-aided searches for reiterated sequences within BPMV M RNA which might explain why ordered RNA is visible in the electron density map of BPMV middle component particles (Chen, Z., Stauffacher, C. V., Li, Y., Schmidt, T., Bomu, W., Kamer, G., Shanks, M., Lomonossoff, G., and Johnson, J. E., 1989, Science 245, 154-159). These searches revealed both the presence of overrepresented pentameric sequences and a consensus sequence which was repeated 15 times within the RNA sequence.
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41
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Coutts RH, Rigden JE, Slabas AR, Lomonossoff GP, Wise PJ. The complete nucleotide sequence of tobacco necrosis virus strain D. J Gen Virol 1991; 72 ( Pt 7):1521-9. [PMID: 1856691 DOI: 10.1099/0022-1317-72-7-1521] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The complete sequence of the RNA genome of tobacco necrosis virus strain D (TNV-D) consisting of 3759 nucleotides has been determined. The positive strand contains five open reading frames (ORFs). The 5'-proximal ORF encodes a 22K protein terminating with an amber codon which may be read through to produce a 82K protein (p82). Two small centrally located ORFs each encode two out-of-frame 7K proteins (p7a and p7b). The 3'-proximal ORF encodes the 29K coat protein (CP), the N terminus of which has been sequenced directly. The genomic organization of TNV-D is very similar to that of TNV-A but differs in the placement of the p7a ORF, which does not overlap the p82 ORF in TNV-D, and in the absence of an ORF downstream of the CP gene in TNV-D. The p82 ORF shows extensive sequence similarity with the putative polymerases of the carmovirus group. This ORF is also as closely related to the corresponding ORF of TNV-A as it is to the corresponding ORF of the tombusvirus cucumber necrosis virus. The amino acid sequence of the TNV-D CP gene is similar to both the TNV-A and southern bean mosaic virus CP genes. Of the two p7 ORFs, p7a exhibits amino acid sequence similarity with corresponding proteins from TNV-A, melon necrotic spot virus, carnation mottle virus, turnip crinkle virus and maize chlorotic mottle virus, whereas the p7b ORF appears to be unique to TNV-A and TNV-D. Only the 3'-terminal three nucleotides of TNV-D genomic RNA are identical to the 3'-terminal nucleotides of the TNV satellite virus.
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42
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Goulden MG, Lomonossoff GP, Wood KR, Davies JW. A model for the generation of tobacco rattle virus (TRV) anomalous isolates: pea early browning virus RNA-2 acquires TRV sequences from both RNA-1 and RNA-2. J Gen Virol 1991; 72 ( Pt 7):1751-4. [PMID: 1856703 DOI: 10.1099/0022-1317-72-7-1751] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Comparison of the 5'-terminal sequences of several tobraviruses suggests that the RNA-2 molecule of the tobacco rattle virus (TRV) anomalous isolate TCM arose from pea early browning virus (PEBV) RNA-2 by acquisition of 3' and 5' sequences from TRV RNA-1 and RNA-2 molecules, respectively. We have identified a region of homology in the RNA-2 molecules of PEBV, TRV and pepper ringspot virus which could have facilitated this recombination.
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43
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Lomonossoff GP, Johnson JE. The synthesis and structure of comovirus capsids. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1991; 55:107-37. [PMID: 1871315 DOI: 10.1016/0079-6107(91)90003-b] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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44
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Goulden MG, Lomonossoff GP, Davies JW, Wood KR. The complete nucleotide sequence of PEBV RNA2 reveals the presence of a novel open reading frame and provides insights into the structure of tobraviral subgenomic promoters. Nucleic Acids Res 1990; 18:4507-12. [PMID: 2388830 PMCID: PMC331271 DOI: 10.1093/nar/18.15.4507] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The 3374 nucleotide sequence of RNA2 from the British PEBV strain SP5 has been determined. The RNA includes three open reading frames flanked by 5' and 3' noncoding regions of 509 and 480 nucleotides. The open reading frames specify coat protein, a 29.6K product homologous to the 29.1K product of TRV(TCM) RNA2 and a 23K product not homologous to any previously described protein. The homology demonstrated between the coat proteins of PRV, TRV and PEBV indicates a common evolutionary origin for these proteins. Upstream of each ORF are located sequences homologous to those with which subgenomic RNAs of other tobraviruses start. Subgenomic RNAs for the expression of the three ORFs may start at these points. On all five tobraviral RNA2 molecules sequenced to date, these sequences were found upstream of the coat protein ORF in association with a strongly-conserved potential secondary structural element. Similar potential structures were identified upstream of other tobraviral ORFs. These structures may contribute to the activity of the tobraviral subgenomic promoter.
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45
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Golemboski DB, Lomonossoff GP, Zaitlin M. Plants transformed with a tobacco mosaic virus nonstructural gene sequence are resistant to the virus. Proc Natl Acad Sci U S A 1990; 87:6311-5. [PMID: 2385595 PMCID: PMC54523 DOI: 10.1073/pnas.87.16.6311] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
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 was also exhibited when plants were inoculated at 100 micrograms/ml with the closely related TMV mutant YSI/1 but was not shown in plants challenged at the same concentrations with the more distantly related TMV strains U2 or L or cucumber mosaic virus. Although the copy number of the 54-kDa gene sequence varied in individual transformants from 1 to approximately 5, the level of resistance in plants was not dependent on the number of copies of the 54-kDa gene sequence integrated. The transformed plants accumulated a 54-kDa gene sequence-specific RNA transcript of the expected size, but no protein product was detected.
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46
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Shanks M, Lomonossoff GP. The primary structure of the 24K protease from red clover mottle virus: implications for the mode of action of comovirus proteases. J Gen Virol 1990; 71 ( Pt 3):735-8. [PMID: 2179468 DOI: 10.1099/0022-1317-71-3-735] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We have determined the nucleotide sequence of the region of red clover mottle virus (RCMV) bottom component RNA which encodes the RCMV equivalent of the cowpea mosaic virus (CPMV) 24K protease. From the alignment of the deduced amino acid sequence of the RCMV 24K protein with that of the homologous protein from CPMV, we speculate on the relative importance of the various amino acid residues which have been implicated in the catalytic mechanism of comovirus proteases.
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47
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Shanks M, Tomenius K, Clapham D, Huskisson NS, Barker PJ, Wilson IG, Maule AJ, Lomonossoff GP. Identification and subcellular localization of a putative cell-to-cell transport protein from red clover mottle virus. Virology 1989; 173:400-7. [PMID: 2596020 DOI: 10.1016/0042-6822(89)90552-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To investigate the mode of gene expression of red clover mottle virus (RCMV) middle component (M) RNA, we have synthesized an oligopeptide corresponding to the predicted carboxy-terminus of the RCMV counterparts of the cowpea mosaic virus (CPMV) 48K and 58K proteins. Using an antiserum raised against this synthetic oligopeptide, we have detected a 43-kDa protein in the 30,000 g pellet from extracts of RCMV-infected cowpea protoplasts. Immunogold cytochemistry further localized this protein to the plasmodesmata of RCMV-infected pea tissue. This subcellular location, taken together with other evidence, suggests that this 43-kDa protein has a role in the cell-to-cell spread of RCMV.
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48
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Holness CL, Lomonossoff GP, Evans D, Maule AJ. Identification of the initiation codons for translation of cowpea mosaic virus middle component RNA using site-directed mutagenesis of an infectious cDNA clone. Virology 1989; 172:311-20. [PMID: 2773321 DOI: 10.1016/0042-6822(89)90133-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A full-length cDNA copy of CPMV M RNA has been cloned downstream of a phage lambda promoter in the plasmid pPMI. Transcripts obtained from this clone can be translated in vitro and replicated in cowpea mesophyll protoplasts in the presence of viral B RNA. We have constructed a series of site-directed mutants of this clone to investigate the mechanism of translation of CPMV M RNA. The results obtained confirm that the AUG at position 161 is used to direct the synthesis of a 105K protein in vitro and the detection of a 58K protein in infected cowpea protoplasts suggests that it is also used in vivo. The synthesis of the 95K protein can be initiated from either of the AUGs at positions 512 and 524, though synthesis of this protein does not appear to be essential for CPMV replication in protoplasts.
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Lommel SA, Weston-Fina M, Xiong Z, Lomonossoff GP. The nucleotide sequence and gene organization of red clover necrotic mosaic virus RNA-2. Nucleic Acids Res 1988; 16:8587-602. [PMID: 3047682 PMCID: PMC338578 DOI: 10.1093/nar/16.17.8587] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Red clover necrotic mosaic virus, a member of the dianthovirus group, is characterized by a genome composed of two nonhomologous single-stranded RNAs of approximately 4.0 (RNA-1) and 1.4 kb (RNA-2). The complete nucleotide sequence of the RNA-2 has been determined. RNA-2 is 1448 nucleotides in length with a 5' terminal m7G cap and no 3' terminal poly-A tail or 5' terminal VPg. An open reading frame beginning at the first initiation codon at nucleotide 80 and ending at nucleotide 1030 has been identified which can encode a polypeptide of 35 kDa. RNA-2 directs the synthesis of a 35 kDa polypeptide in vitro. SP6 and T7 transcripts from full length RNA-2 cDNA clones directed the synthesis of a polypeptide with the same electrophoretic mobility as the polypeptide directed from authentic RNA-2. Clones with various 3' terminal deletions both outside and within the 35 kDa open reading frame were transcribed and translated in vitro to define the limits of the 35 kDa open reading frame. A second, small open reading frame capable of encoding a polypeptide of 4.9 kDa was also indicated from the sequence; however, there was no evidence for a protein product of that size. RNA-2 is presumed to be monocistronic and encode a cell-to-cell movement function. A small but significant amino acid sequence homology was observed with the brome mosaic virus RNA-3a polypeptide.
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Domier LL, Franklin KM, Shahabuddin M, Hellmann GM, Overmeyer JH, Hiremath ST, Siaw MF, Lomonossoff GP, Shaw JG, Rhoads RE. The nucleotide sequence of tobacco vein mottling virus RNA. Nucleic Acids Res 1986; 14:5417-30. [PMID: 3737407 PMCID: PMC311550 DOI: 10.1093/nar/14.13.5417] [Citation(s) in RCA: 149] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The nucleotide sequence of the RNA of tobacco vein mottling virus, a member of the potyvirus group, was determined. The RNA was found to be 9471 residues in length, excluding a 3'-terminal poly(A) tail. The first three AUG codons from the 5'-terminus were followed by in-frame termination codons. The fourth, at position 206, was the beginning of an open reading frame of 9015 residues which could encode a polyprotein of 340 kDa. No other long open reading frames were present in the sequence or its complement. This AUG was present in the sequence AGGCCAUG, which is similar to the consensus initiation sequence shared by most eukaryotic mRNAs. The chemically-determined amino acid compositions of the helper component and coat proteins were similar to those predicted from the nucleotide sequence. Amino acid sequencing of coat protein from which an amino-terminal peptide had been removed allowed exact location of the coat protein cistron. A consensus sequence of V-(R or K)-F-Q was found on the N-terminal sides of proposed cleavage sites for proteolytic processing of the polyprotein.
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