Identification, Mapping, and In Vitro Translation of Campoletis sonorensis Virus mRNAs from Parasitized Heliothis virescens Larvae

Abstract

Expression of Campoletis sonorensis virus (CsV) in parasitized Heliothis virescens larvae was investigated by Northern blot analysis of poly(A) + mRNAs isolated from H. virescens larvae at various times after parasitization by C. sonorensis. At least 12 CsV mRNAs were detected in parasitized H. virescens larvae. Injection of nonparasitized H. virescens larvae with purified CsV resulted in a pattern of viral mRNAs similar to that observed in naturally parasitized larvae. With CsV DNA restriction fragments which contained expressed sequences, individual CsV mRNAs were mapped to the superhelical DNAs of the viral genome. Two gene-specific probes, which consisted of cloned S1 nuclease-protected restriction fragments, each hybridized to several CsV superhelical DNAs, suggesting that some CsV genes may be shared on several superhelical DNAs. Cloned restriction fragments containing sequences which flank the expressed sequences also hybridized to numerous CsV superhelical DNAs. Some CsV proteins were identified by in vitro translation of hybrid-selected CsV mRNAs.