Persistent expression of a newly characterized Hyposoter didymator polydnavirus gene in long-term infected lepidopteran cell lines

An Hyposoter didymator ichnovirus (HdlV) gene was stably maintained and eff iciently transcribed in lepidopteran cell lines more than 3 years after Hdl V infection. This K-gene had two introns and the fully spliced cDNA, named K19, comprised a short open reading frame and a long 3'-untranslated region with 13 imperfectly repeated sequences (44 to 102 nt). Transcripts related to the K-gene were detected in several long-term infected cell lines (Sf9, Spodoptera littoralis haemocytes, Trichoplusia ni). Conversely, no transcr ipts related to seven other viral cDNAs were detected, suggesting that the K-related DNA is selectively retained in longterm infected Sf9 cells. The f unction of the K-gene product and its association with stably transformed i nsect cell lines remains to be investigated.