Integration into the genome of the host cell is an obligatory step in the replication of retroelements. This feature accounts for the fact that these elements are both potential mutagens as well as vectors suitable for long-term gene therapy. Recently, many studies have reported that proviral insertion is not random but, rather, targets specific regions in the genome. Additionally, it has become clear that this process is highly regulated at the molecular level. Both viral proteins and cellular factors participate in the integration step, explaining why different retroelements have distinct integration profiles. This review describes recent advances about the integration of retroelements, focusing particularly on the mechanisms involved in the selectivity and specificity of integration and the chromatin-anchoring step, which precedes the insertion of the provirus.
Keywords: Gag; integrase; retrotransposons; retrovirus.