Meints R.H.
Oregon State University, Center for Gene Research and Biotechnology, Corvallis, OR 97333
A persistent dsDNA virus (FsV) infection in the algal genus Feldmannia occurs within the sporophyte meiotic sporangia that normally produce zoospores. No trace of virus is evident in vegetative cells of sporophyte, and gametophytes produce no virus at all. CHEF electrophoresis demonstrates two virus genome size-classes of 158 and 178 which map as circles. Repetitive sequences (173 bp) were found in virus DNA. In an encrypted sequence of FsV, a large (50 kbp) repeat insert occurs within a serine/threonine protein kinase gene. Both the major capsid protein and the DNA polymerase gene have been isolated and characterized. Two transcriptionally active open reading frames which contain an ATP binding site and a "RING" zinc finger motif were found. The capsid protein is related to that of the Iridoviruses and less so to African Swine fever virus. Here we will describe the insertion sites of replicationally active FsV integrated within the host genome. The viral insertion site occurs in the viral BamHI-fragment A (B26.0A) of small genome size class viruses. The viral genomes of both size classes open at the precise base pair, but insertion of each is at different, but related, places of the host genome. These sites have been cloned and sequenced.