A HIGHLY DIVERGENT RETROVIRAL SEQUENCE IN THE TUATARA (SPHENODON)

Vertebrate retroviruses have been classified into a number of differen t genera, and although many mammalian and avian examples have been cha racterized, less information exists about the retroviruses present wit hin other vertebrate classes. We designed oligonucleotide primers agai nst two highly conserved motifs within retroviral protease and reverse transcriptase genes and used them to isolate a retroviral fragment fr om the reptile tuatara (Sphenodon). Sequence analysis of this element, termed SpeV, demonstrated that it is substantially different from pre viously reported viruses, and that it cannot easily be placed into any known retroviral genus. Furthermore SpeV suggests that there may be s ome major differences between the retroviral populations found in rept iles and those present in mammals and birds. (C) 1995 Academic Press, Inc.