reverse-genetics-mediated-recovery-of-infectious-murine-norovirus

Reverse Genetics Mediated Recovery of Infectious Murine Norovirus

Human noroviruses are responsible for most cases of human gastroenteritis (GE) worldwide and are recurrent problem in environments where close ...

Two features of viral quasispecies are reviewed: the presence of memory genomes as minority components of their mutant spectra, and viral extinction due to enhanced mutagenesis. Memory has been documented with several genetic markers of the important animal picornavirus foot-and-mouth disease virus (FMDV). The presence of memory genomes in viral quasispecies may accelerate their adaptive response whenever a selective constraint has already been experienced by a viral population during previous stages of its evolution. Enhanced mutagenesis has been shown to lead to losses of infectivity of a number of RNA viruses: poliovirus, vesicular stomatitis virus, human immunodeficiency virus type 1 and FMDV. These observations, based on the theoretical prediction of the existence of a copying error-threshold for maintenance of genetic information, may contribute to the development of a new antiviral strategy.

Emergence and selection of RNA virus variants: memory and extinction.

Entstehung und Selektion von RNA-Virus-Varianten: Ged&#xE4;chtnis und vom Aussterben bedroht.

A mutant poliovirus (PV) encoding a change in its polymerase (3Dpol) at a site remote from the catalytic center (G64S) confers reduced sensitivity to ribavirin and forms a restricted quasispecies, because G64S 3Dpol is a high-fidelity enzyme. A foot-and-mouth disease virus (FMDV) mutant that encodes a change in the polymerase catalytic site (M296I) exhibits reduced sensitivity to ribavirin without restricting the viral quasispecies. In order to resolve this apparent paradox, we have established a minimal kinetic mechanism for nucleotide addition by wild-type (WT) FMDV 3Dpol that permits a direct comparison to PV 3Dpol as well as to FMDV 3Dpol derivatives. Rate constants for correct nucleotide addition were on par with those of PV 3Dpol, but apparent binding constants for correct nucleotides were higher than those observed for PV 3Dpol. The A-to-G transition frequency was calculated to be 1/20,000, which is quite similar to that calculated for PV 3Dpol. The analysis of FMDV M296I 3Dpol revealed a decrease in the calculated ribavirin incorporation frequency (1/8,000) relative to that (1/4,000) observed for the WT enzyme. Unexpectedly, the A-to-G transition frequency was higher (1/8,000) than that observed for the WT enzyme. Therefore, FMDV selected a polymerase that increases the frequency of the misincorporation of natural nucleotides while specifically decreasing the frequency of the incorporation of ribavirin nucleotide. These studies provide a mechanistic framework for understanding FMDV 3Dpol structure-function relationships, provide the first direct analysis of the fidelity of FMDV 3Dpol in vitro, identify the beta9-alpha11 loop as a (in)fidelity determinant, and demonstrate that not all ribavirin-resistant mutants will encode high-fidelity polymerases.

Determinants of RNA-dependent RNA polymerase (in)fidelity revealed by kinetic analysis of the polymerase encoded by a foot-and-mouth disease virus mutant with reduced sensitivity to ribavirin.

Article	Year
Journal of molecular biology\| PubMed ID: 11786012	2002
Emergence and selection of RNA virus variants: memory and extinction. Virus research\| PubMed ID: 11885948	2002
Journal of virology\| PubMed ID: 15016853	2004
Journal of molecular biology\| PubMed ID: 15136042	2004
The Journal of biological chemistry\| PubMed ID: 15294895	2004
Journal of molecular biology\| PubMed ID: 16216271	2005
Current opinion in structural biology\| PubMed ID: 16364629	2006
The EMBO journal\| PubMed ID: 16456546	2006
Journal of virology\| PubMed ID: 17151116	2007
Proceedings of the National Academy of Sciences of the United States of America\| PubMed ID: 17517631	2007
Journal of molecular biology\| PubMed ID: 18158159	2008
Journal of molecular biology\| PubMed ID: 18662697	2008
Determinants of RNA-dependent RNA polymerase (in)fidelity revealed by kinetic analysis of the polymerase encoded by a foot-and-mouth disease virus mutant with reduced sensitivity to ribaviri... Journal of virology\| PubMed ID: 18829745	2008
Journal of virology\| PubMed ID: 19710148	2009
Journal of virology\| PubMed ID: 20392853	2010
PloS one\| PubMed ID: 20505767	2010
PLoS pathogens\| PubMed ID: 20865120	2010
Future medicinal chemistry\| PubMed ID: 21426129	2009
PLoS genetics\| PubMed ID: 21437265	2011
The Journal of general virology\| PubMed ID: 22495235	2012

Armando Arias

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