Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2007
Publication Date: 5/1/2007
Citation: Perera, O.P., Green, T.B., Stevens, S.M., White, S.E., Becnel, J.J. 2007. Proteins associated with Culex nigripalpus Nucleopolyhedrovirus (CuniNPV) occluded virions. Virology. 81(9):4585-4590. 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 structural proteins of virions to better understand how this virus exploits the mosquito host. This information will enhance the development of this virus as a biological control agent for mosquitoes.
Technical Abstract: Occlusion derived virions (ODVs) of the nucleopolyhedrovirus of Culex nigripalpus (CuniNPV) were purified by sucrose density gradient ultracentrifugation and the proteins were separated on SDS-PAGE and isolated. Proteins were identified using Edman sequencing, matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, nano-electrospray quadrupole time-of-flight mass spectrometry (GeLC-MS/MS), or a combination of these methods. Half of the 44 polypeptide sequences identified in this analysis were unique orfs encoded by the CuniNPV genome and did not show any similarity to any other sequences present in protein databases. Of the 22 polypeptides that showed similarities to other baculovirus encoded proteins, only 17 sequences have previously been identified as structural proteins. The newly identified CuniNPV structural proteins cun058, cun059, cun087, cun106, and cun109 are homologues of Autographa californica nucleopolyhedrovirus (AcMNPV) ORFs 68, 62, 98, 81, and 2, respectively. The products of four genes, namely, lef-1 (cun045), alkaline exonuclease (cun054), helicase (cun089), and DNA polymerase (cun091) were not detected in the CuniNPV ODV preparations. These four genes are conserved among all annotated baculovirus genomes and their homologues have been detected in the ODV of AcMNPV.