Structure and function of replicative proteins from alphaviruses


Project description
Alphaviruses have a positive-stranded RNA genome that can serve as the mRNA for translation of the polyprotein precursor that is autocatalytically processed to the four non-structural viral proteins by the virus-encoded protease in nsP2. The non-structural proteins form the transcription/replication complex. The nsP1 protein is implicated in capping of viral RNAs. The nsP2 gene encodes a putative helicase and a protease , which presents a unique fold distantly related to that of known cysteine proteases. This protease domain is linked to the downstream domain of degenerated O-methyltransferase fold that may regulate transcription/replication through RNA binding. The nsP3 protein is required for RNA replication. Its N-terminal sequence reveals a macro domain, the crystal structures of which have recently been determined (Malet et al., 2009). The nsP4 protein carries the viral RNA dependant RNA Polymerase (RdRP), the key activity for the viral replication/transcription. Unlike the RdRP of Flaviviridae or Picornaviridae, the RdRP can't be active in vitro without adding nsPs. The aim of the project is to understand the molecular interactions between the different nsPs that are involved in the regulation of the polymerase. This first study will be useful to i) design the miniml set of proteins and RNAs required to launch relevant structural studies of nsP4 and possibly other nsps ii) set up an in vitro polymerase assay. Both structural and functional data will ultimately serve to launch rational drug design.

Host institute
The student will be located at AFMB CNRS/Université de la Méditerranée, Marseille, France). He/she will have access to the facilities of the lab to drive his (or her) multidisciplinary project (cell culture, biochemistry/enzymology, structural biology) and will also benefit from the antiviral facilities provided by the EUVIRNA consortium.
Supervisor: Dr. Bruno Canard

This position has been filled.