Replication of the coronavirus genome: A paradox among positive-strand RNA viruses
Résumé
Coronavirus (CoV) genomes consist of positive-sense single-
stranded RNA and are among the largest viral RNAs known to
date (30 kb). As a result, CoVs deploy sophisticated mecha-
nisms to replicate these extraordinarily large genomes as well
as to transcribe subgenomic messenger RNAs. Since 2003, with
the emergence of three highly pathogenic CoVs (SARS-CoV,
MERS-CoV, and SARS-CoV-2), significant progress has been
made in the molecular characterization of the viral proteins
and key mechanisms involved in CoV RNA genome replication.
For example, to allow for the maintenance and integrity of their
large RNA genomes, CoVs have acquired RNA proofreading 30-
50 exoribonuclease activity (in nonstructural protein nsp14). In
order to replicate the large genome, the viral-RNA–dependent
RNA polymerase (RdRp; in nsp12) is supplemented by a
processivity factor (made of the viral complex nsp7/nsp8),
making it the fastest known RdRp. Lastly, a viral structural
protein, the nucleocapsid (N) protein, which is primarily
involved in genome encapsidation, is required for efficient viral
replication and transcription. Therefore, CoVs are a paradox
among positive-strand RNA viruses in the sense that they use
both a processivity factor and have proofreading activity
reminiscent of DNA organisms in addition to structural pro-
teins that mediate efficient RNA synthesis, commonly used by
negative-strand RNA viruses. In this review, we present a his-
torical perspective of these unsuspected discoveries and detail
the current knowledge on the core replicative machinery
deployed by CoVs.
Fichier principal
Coronavirus RNA-synthesis machinery- a paradox among (+) RNA viruses.pdf (1.7 Mo)
Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte