Switch from translation to RNA replication in a positive-stranded RNA virus

Gamarnik, Andrea V.; Andino, Raul

doi:10.1101/gad.12.15.2293

Cited by 465 publications

(478 citation statements)

References 48 publications

Supporting

Mentioning

465

Contrasting

Unclassified

Order By: Relevance

“…Cycloheximide completely blocked the regeneration of RNA synthesis (Fig. 6a), in principle this could result from a blockade of RNA replication as well as inhibition of protein synthesis since ribosomes remain associated with the RNA in the presence of this drug (Barton et al, 1999), although Gamarnik & Andino (1998) showed that inhibition of protein synthesis with cycloheximide strongly stimulated RNA replication in their cell-free translation/replication system. However, puromycin, which causes the release of ribosomes from the RNA, also completely abolished the increase in RNA following removal of gua-HCl (Fig.…”

Section: Discussionmentioning

confidence: 99%

Dynamics of picornavirus RNA replication within infected cells

Belsham

Normann

2008

Journal of General Virology

View full text Add to dashboard Cite

Replication of many picornaviruses is inhibited by low concentrations of guanidine. Guanidine-resistant mutants are readily isolated and the mutations map to the coding region for the 2C protein. Using in vitro replication assays it has been determined previously that guanidine blocks the initiation of negative-strand synthesis. We have now examined the dynamics of RNA replication, measured by quantitative RT-PCR, within cells infected with either swine vesicular disease virus (an enterovirus) or foot-and-mouth disease virus as regulated by the presence or absence of guanidine. Following the removal of guanidine from the infected cells, RNA replication occurs after a significant lag phase. This restoration of RNA synthesis requires de novo protein synthesis. Viral RNA can be maintained for at least 72 h within cells in the absence of apparent replication but guanidine-resistant virus can become predominant. Amino acid substitutions within the 2C protein that confer guanidine resistance to swine vesicular disease virus and foot-and-mouth disease virus have been identified. Even when RNA synthesis is well established, the addition of guanidine has a major impact on the level of RNA replication. Thus, the guanidine-sensitive step in RNA synthesis is important throughout the virus life cycle in cells.

show abstract

Section: Discussionmentioning

confidence: 99%

Dynamics of picornavirus RNA replication within infected cells

Belsham

Normann

2008

Journal of General Virology

View full text Add to dashboard Cite

show abstract

“…This transition from translation to replication must be regulated at a temporal level to accommodate both processes (13). We posit that 1a inhibition of translation could function as a temporal switch.…”

Section: Discussionmentioning

confidence: 99%

Selective Repression of Translation by the Brome Mosaic Virus 1a RNA Replication Protein

Gopinath

Kao

2007

J Virol

View full text Add to dashboard Cite

Differential expression of viral replication proteins is essential for successful infection. We report here that overexpression of the brome mosaic virus (BMV) 1a protein can repress viral RNA replication in a dosagedependent manner. Using RNA replication-incompetent reporter constructs, repression of translation from BMV RNA1 and RNA2 was observed, suggesting that the effect on translation of the BMV RNA replication proteins is responsible for the decrease in RNA levels. Furthermore, repression of translation by 1a required the B box in the 5 -untranslated region (5 UTR); BMV RNA3 that lacks a B box in its 5 UTR is not subject to 1a-mediated translational inhibition. Mutations in either the methyltransferase or the helicase-like domains of 1a reduced the repression of replication and translation. These results suggest that in addition to its known functions in BMV RNA synthesis, 1a also regulates viral gene expression.Viruses must produce their gene products in the proper amounts and with the appropriate timing. Failure to do so can lead to innate defense responses from the host that may act on RNA replication intermediates (47). A number of mechanisms can contribute to the differential expression of viral products, such as ribosome shunting, leaky scanning, frameshifting, functional recoding, and reinitiation (11, 12). For Sindbis virus and Tobacco mosaic virus, with single genomic RNAs, the expression of the RNA-dependent RNA polymerase is decreased by readthrough of leaky termination codons (27,37,44,45). Translational control also plays an important role in regulating viral gene expression in negative-sense RNA viruses and retroviruses (19,28,31,41,49). Regulation of protein production from segmented plus-strand RNA viruses is less well understood.Brome mosaic virus (BMV), a member of the alphavirus-like superfamily of RNA viruses, is a model segmented positivestrand RNA virus. The BMV genome consists of three capped, messenger-sense genomic RNAs which have a tRNA-like structure within the 3Ј-untranslated region (3Ј UTR). Genomic RNA1 and RNA2 encode nonstructural proteins 1a and 2a, respectively, which direct RNA replication (33). Genomic RNA3 is a bicistronic RNA encoding the cell-to-cell movement protein (MP) and the coat protein (CP). The MP is translated from RNA3, whereas the 3Ј-proximal coat protein is translated from a subgenomic RNA4 that is made using minus-strand RNA3 as the template (33). In addition to replication in various plant species, BMV can replicate and transcribe its genome in Saccharomyces cerevisiae (20).The multifunctional 1a protein contains two domains separated by a proline-rich sequence. The N-terminal domain contains activities for 7-methyl-guanosine methyltransferase and covalent GTP binding required for viral RNA capping (2, 23). The C-terminal domain contains all of the motifs of the DEAD box RNA helicase domain, with ATPase and GTPase activities (24, 48). 1a is the primary viral protein determinant for the subcellular localization of the BMV RNA replication complex (9, 39, ...

show abstract

“…It is unlikely that the advancing polymerase itself could remove ribosomes in front of it; indeed it has been found that the poliovirus RNA-dependent RNA polymerase is unable to synthesize RNA on viral RNA templates undergoing translation. Evidence has been obtained that the poliovirus 3CD protein, the precursor of the 3D polymerase, controls the switch from translation to replication by binding to a cloverleaf structure at the 5'-end of the genomic RNA and preventing further initiation of translation (Gamarnik & Andino 1998). For phage Q b, the switch is achieved by the S1 host component of the replicase, which binds to ribosome-binding sites on Q b RNA and prevents further binding of ribosomes (Blumenthal & Carmichael 1979).…”

Section: Regulation Of Tmv Rna Synthesismentioning

confidence: 99%

Replication of tobacco mosaic virus RNA

Buck

1999

Phil. Trans. R. Soc. Lond. B

100

View full text Add to dashboard Cite

The replication of tobacco mosaic virus (TMV) RNA involves synthesis of a negative-strand RNA using the genomic positive-strand RNA as a template, followed by the synthesis of positive-strand RNA on the negative-strand RNA templates. Intermediates of replication isolated from infected cells include completely double-stranded RNA (replicative form) and partly double-stranded and partly single-stranded RNA (replicative intermediate), but it is not known whether these structures are double-stranded or largely single-stranded in vivo. The synthesis of negative strands ceases before that of positive strands, and positive and negative strands may be synthesized by two di¡erent polymerases. The genomic-length negative strand also serves as a template for the synthesis of subgenomic mRNAs for the virus movement and coat proteins. Both the virus-encoded 126-kDa protein, which has amino-acid sequence motifs typical of methyltransferases and helicases, and the 183-kDa protein, which has additional motifs characteristic of RNA-dependent RNA polymerases, are required for e¤cient TMV RNA replication. Puri¢ed TMV RNA polymerase also contains a host protein serologically related to the RNA-binding subunit of the yeast translational initiation factor, eIF3. Study of Arabidopsis mutants defective in RNA replication indicates that at least two host proteins are needed for TMV RNA replication. The tomato resistance gene Tm-1 may also encode a mutant form of a host protein component of the TMV replicase. TMV replicase complexes are located on the endoplasmic reticulum in close association with the cytoskeleton in cytoplasmic bodies called viroplasms, which mature to produce`X bodies'. Viroplasms are sites of both RNA replication and protein synthesis, and may provide compartments in which the various stages of the virus mutiplication cycle (protein synthesis, RNA replication, virus movement, encapsidation) are localized and coordinated. Membranes may also be important for the con¢guration of the replicase with respect to initiation of RNA synthesis, and synthesis and release of progeny single-stranded RNA.

show abstract

Switch from translation to RNA replication in a positive-stranded RNA virus

Cited by 465 publications

References 48 publications

Dynamics of picornavirus RNA replication within infected cells

Dynamics of picornavirus RNA replication within infected cells

Selective Repression of Translation by the Brome Mosaic Virus 1a RNA Replication Protein

Replication of tobacco mosaic virus RNA

Contact Info

Product

Resources

About