NEW INSIGHT ON THE ROLE OF EXTRACHROMOSOMAL RETROVIRAL DNA

During infection with different retroviruses, high levels of unintegra ted extrachromosomal DNA accumulate in infected cells. While extrachro mosomal linear DNA is the immediate precursor of the integrated provir us, the function, if any, of extrachromosomal circular DNA has been un clear. Several groups have attempted to address the possible function, activity, and importance of this unintegrated DNA during the life cyc le of retroviruses and the course of retroviral-associated diseases. T his review summarizes recent work in this field and tries to analyze s ome aspects of extrachromosomal forms of retroviral DNA and their poss ible application as a molecular biological tool.