Isolation and characterization of an apoptotic suppressor gene from spodoptera littoralis nucleopolyhedrovirus

The Spodoptera littoralis nucleopolyhedrovirus was able to suppress apoptosis triggered by an AcNPV p35 null mutant. To identify the putative apoptotic suppressor gene of SlNPV, overlapping cosmid clones representing the entire SlNPV genome, were individually cotransfected along with genomic DNA of an AcNPV p35 null mutant. Using this complementation assay we identified a novel SlNPV gene, inhibitor of apoptosis, SI p49. The Sl p49 sequence predicted a 49-KD polypeptide with about 48.8% identity to p35 of AcNPV. Recombinant AcNPVs, deficient in p35 and bearing the SI p49 gene, showed successful productive infection in Sf9 cells indicating that SI p49 is a functional homolog of p35.