Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 23, 2005
Publication Date: May 15, 2006
Citation: Perera, O.P., Valles, S.M., Green, T.B., White, S.E., Strong, C.A., Becnel, J.J. 2006. MOLECULAR ANALYSIS OF AN OCCLUSION BODY PROTEIN FROM CULEX NIGRIPALPUS NUCLEOPOLYHEDROVIRUS (CUNINPV). Journal of Invertebrate Pathology. 91(1):35-42. Interpretive Summary: A naturally occurring virus that kills mosquitoes has been discovered by ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology, Gainesville Florida. Mosquito species susceptible to this virus are important vectors of St. Louis Encephalitis, Eastern Equine Encephalitis and West Nile Virus in the United States. This new virus kills larval mosquitoes quickly and over extended periods. We have conducted a molecular study to characterize the major protein that protects the virus when released into the environment. This information will enhance the development of this virus as a biological control agent for mosquitoes.
Technical Abstract: CUN085 is an occlusion body (OB) protein from the nucleopolyhedrovirus of Culex nigripalpus (CuniNPV). SDS-PAGE analysis indicated that the CuniNPV OB protein is about 3 times the size (~90 kDa) of characterized nucleopolyhedrovirus (NPVs) and granulovirus (GVs) OB proteins. Rapid amplification of cDNA ends (RACE), RNase protection assay, real time PCR, and protein sequencing were used to characterize CUN085 from CuniNPV. RACE data indicated that the transcriptional start and termination sites for the CUN085 gene yielded a polypeptide comprised of 822 amino acids indicating that translation likely initiates within a larger 882 amino acid orf that was originally predicted from the CuniNPV genome sequence. Transcription of CUN085 started at a consensus baculovirus late transcription start site TAAG at nucleotide position 75433 of the CuniNPV genome sequence. RNase protection assays and quantitative real time PCR show that the CUN085 transcript is first detected in mosquito larvae at approximately 6 hours after infection with CuniNPV and its prevalence increased progressively over the subsequent 18 hours.