Diversity of errantivirus (retrovirus) sequences in two cell lines used for baculovirus expression, Spodoptera frugiperda and Trichoplusia ni

To determine the diversity of retroviruses (errantiviruses) in cell lines used for baculovirus expression, degenerate primers were designed complementary to conserved regions of lepidopteran errantivirus reverse transcriptase genes. These primers were used to PCR amplify sequences from DNA isolated from Spodoptera frugiperda (Sf-9) and Trichoplusia ni (Hi-5) cell lines. Cloning, sequencing, and phylogenetic analysis of over 20 PCR products from each cell line demonstrated the presence of diverse populations of retrovirus sequences comprising at least six major lineages.