Cloning of the chandipura virus phosphoprotein encoding gene and its expression in Escherichia coli

Chandipura (CHP) virus, a member of the vesiculovirus genus within the Rhabdoviridae family, was first isolated from human patients in India. The full length phosphoprotein P gene of CHP have been cloned and expressed in Escherichia coli using the T7 polymerase-based pET-3 series of expression vectors. Under optimal conditions of induction with IPTG, the recombinant P protein constituted 35% of the total bacterial protein. The bacterially expressed protein was found to be phosphate-free. Deletion analysis suggested that the anomalous mobility of the P protein was due to its high acidity. The expressed protein can be phosphorylated in vitro by the extracts prepared from baby hamster kidney cells or rabbit reticulocytes. The cellular kinase involved in phosphorylation appears to be casein kinase II.