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Title: THE V-TREX GENE OF THE ANTICARSIA GEMMATAILS MULTICAPSID NUCLEOPOLYHEDROVIRUS ENCODES FOR A FUNCTIONAL 3'TO 5'EXONUCLEASES.

Author
item SLACK, JEFFREY
item SHAPIRO, MARTIN

Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2005
Publication Date: 6/1/2005
Citation: Slack, J.M., Shapiro, M. 2005. The v-trex gene of the anticarsia gemmatails multicapsid nucleopolyhedrovirus encodes for a functional 3'to 5'exonucleases.. Journal of General Virology. 86:1637-1643.

Interpretive Summary: Baculoviruses are germs that cause disease only in insects. The baculovirus called Anticarsia gemmatalis Multicapsid Nucleopolyhedrovirus (AgMNPV) is used as a biological insecticide against agricultural insect pests. After baculoviruses have been sprayed in the field to control insect pests, sunlight causes baculovirus DNA to break. Baculoviruses with broken DNA cannot infect and kill insects. AgMNPV produces a protein called V-TREX. We developed a test that showed that the V-TREX protein could help to repair broken DNA. AgMNPV may be producing the V-TREX protein to repair AgMNPV DNA that has become broken after exposure to sunlight. Our study suggests that V-TREX is a factor that helps to make AgMNPV last longer in the field and therefore makes AgMNPV a more successful baculovirus insecticide.

Technical Abstract: The v-trex gene of the Anticarsia gemmatalis Multicapsid Nucleopolyhedrovirus (AgMNPV) is the first baculovirus gene to be described with significant homology to a three prime exonuclease. Choristoneura fumiferana MNPV (CfMNPV) is the only other baculovirus to have a complete v-trex homologue. The v-trex gene is an early gene that is expressed by AgMNPV at least 3h post infection. In the present study, we cloned the AgMNPV v-trex gene into the baculovirus Autographa californica MNPV under the regulation of a polyhedrin promoter. The resulting virus produced an abundant, soluble protein that migrated at the apparent size of 23.7 kDa. Soluble lysates contained 3' to 5' exonuclease activity that was 2000 fold above that of wt virus infected cells. The exonuclease activity was inhibited by EDTA and was activated in the presence of Mg+2 and to a lesser extent, in the presence of Mn+2. From this study, the AgMNPV v-trex gene is concluded to encode for an independently active 3' to 5' exonuclease.