The integration of viral DNA into the host cell chromosome is an essential feature of the retroviral life cycle. The integration reaction requires cis-acting sequences at the end of linear viral DNA and a trans-acting product of the pol gene, the integration protein (IN). Previously, we demonstrated that avian sarcoma-leukosis virus (ASLV) IN is able to carry out the first step in the integration process in vitro: nicking of the ends of linear viral DNA. In this paper, using two independent assays, we demonstrate that IN, alone, is sufficient to carry out the second step: cleavage and joining to the target DNA. These results demonstrate that the retroviral IN protein is an integrase.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)