In vivo integration of Campoletis sonorensis ichnovirus genomic segments into Heliothis virescens DNA

Polydnaviruses (PDVs) are a group of insect viruses that reside within certain parasitoid wasps. When parasitizing, these wasps inject an egg as well as PDV into caterpillar hosts. The PDV suppresses the caterpillar's immune system thus allowing the wasp egg to develop. PDVs share an intimate relationship with their wasp host; they do not replicate outside of the wasp body and their genome is stably integrated into that of the wasp. The PDV relationship with their caterpillar host, however, is supposedly transient, and the genome persists only as circular segments. This view was challenged when certain polydnavirus segments were found to persist in PDV-exposed lepidopteran cells, stably integrating into their cell genome. To explore this phenomenon in vivo, we injected fourth instar Heliothis virescens moth larvae with the Campoletis sonorensis ichnovirus (CsIV), raised them to adulthood and screened for the presence of eleven CsIV segments, using PCR. Ten out of eleven segments were detected in at least one adult. One detected segment, G2, was analyzed for its integration site in the wasp genome, precursory to integration site analysis in injected lepidopterans. We seek to completely describe the integration patterns of all CsIV segments that persist in whole organisms. The characterization of such integrating DNA molecules can be directly applied to medical and biotechnology fields in areas such as gene therapy and transfer.