MODIFICATION OF RETROVIRAL RNA BY DOUBLE-STRANDED-RNA ADENOSINE-DEAMINASE

In this report, we describe a recombinant provirus generated during in vitro passage that contains a short region of adenosine-to-guanosine hypermutation. The hypermutated region is restricted to complementary sequences present in the recombinant provirus. We propose that a duple x was formed in the recombinant RNA prior to reverse transcription. Th is duplex was a substrate for double-stranded RNA adenosine deaminase, an activity found in all cells examined that deaminates A in double-s tranded RNA, converting it to inosine, which is further converted to a guanosine by reverse transcription. It appears that cis viral sequenc es facilitated the A-->G transitions.