laboratoire architecture et fonction des macromolécules biologiques (AFMB),
UMR 7257 - CNRS,
ESIL Case 925, 13288 Marseille,
The discovery of a new coronavirus (CoV) as the causative agent of the severe acute respiratory syndrome (SARS) pandemic outbreak in 2003 has stimulated a number of studies on the molecular biology of SARS-CoV and related viruses. This research has provided significant new insight into functions and activities of the CoV replication-transcription complex, a multi-protein complex that directs coordinated processes of both continuous and discontinuous RNA synthesis to replicate and transcribe the large CoV genome, a single-stranded, positive-sense RNA of ∼30 kilobases. In this review, we summarize current understanding of the expression and functions of key replicative enzymes, such as RNA polymerases, ribonucleases, methyltransferases and other replicase gene encoded proteins involved in genome expression, virus-host interactions and other processes. Collectively, these recent studies reveal fascinating details of a huge enzymatic machinery unique in the RNA virus world.