Les protéines non structurales des Alphavirus : rôle dans la réplication et l'interaction du virus avec la cellule hôte.

Alphaviruses (genus of the family Togaviridae) are emergent arthropod borne viruses. They can cause mild to severe diseases including fever, arthritis, and in certain cases encephalitis leading to neurological sequels. Alphaviruses are enveloped, single-stranded and positive-sense RNA viruses. The genomic RNA encodes for two non-structural proteins (P123 and P1234) ; which are cleaved post-translationally to generate four proteins nsP1 to 4. These nsPs perform viral replication and transcription. Studies on different viruses pointed out that nsPs are associated to increased virulence and are implicated in the shut off of host antiviral defense systems. The present paper reports the latest hypothesis regarding the evolution and the spread of alphaviruses. Moreover, it reviews the recent discoveries concerning the role of nsPs in viral replication and virus-host interactions. The elucidation and the understanding of nsPs function is a prerequisite for the development of potent and selective antiviral drugs.