Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 26, 2003
Publication Date: July 20, 2003
Citation: Gundersen, D.E., Lynn, D.E. 2003. Polydnavirus integration in gypsy moth cells.. Society for Invertebrate Pathology Annual Meeting.
Polydnavirus integration in gypsy moth cells.
D.E. Gundersen-Rindal and D. E. Lynn
U.S. Department of Agriculture, Insect Biocontrol Laboratory, Beltsville, MD 20705
The long-term persistence of polydnavirus (PDV) DNA in infected lepidopteran cell cultures suggests that at least some of the virus genome becomes integrated permanently into the lepidopteran cell genome. To investigate this, cloned libraries were prepared from two different Lymantria dispar (gypsy moth) cell lines that had been maintained in continuous culture for more than five years post infection with the braconid Glyptapanteles indiensis PDV (GiPDV). Junction clones containing both insect chromosomal and polydnaviral sequences were isolated. Precise integration junction sites were identified by sequence comparison of linear (integrated) and circular forms of the GiPDV genome segment F, from which viral sequences originated. Host chromosomal sequences at the site of integration varied between the two L. dispar cell lines though virus sequence junctions were identical and contained a palindromic repeat. The chromosomal site of one junction clone contained sequences with structural similarity to a retrotransposon, encoding a putative reverse transcriptase and integrase, upstream of the putative site of viral integration. The GiPDV genome segment F does not encode any self- replication or -insertion proteins, suggesting a host-derived mechanism may be responsible for its in vitro integration.