ROLE OF CELLULAR KINASES IN THE GENE-EXPRESSION OF NONSEGMENTED NEGATIVE STRAND RNA VIRUSES

Nonsegmented negative strand RNA viruses package an RNA-dependent RNA polymerase composed of two subunits, a large protein L and a phosphopr otein P, for transcription and replication of their genome RNAs. The R NA polymerase activity resides within the L protein, while the P prote in acts as a transcription factor or transactivator of the polymerase. Since P protein is heavily phosphorylated and phosphorylation is know n to regulate function of many viral as well as cellular proteins, the role of phosphorylation of P protein in the gene expression of this g roup of RNA viruses has recently been investigated. Through expression in bacteria the P protein was produced in targe quantity in the nonph osphorylated form and involvement of cellular kinase(s) in its phospho rylation was studied. Casein kinase II and/or protein kinase C have be en shown to play a critical role in the activation of P protein in tra nscription. These findings have opened up a new avenue for studying an important regulatory step in virus gene expression that may lead to t he development of an effective antiviral agent.