Central Core Domain of Retroviral Integrase Is Responsible for Target Site Selection

Integration of retroviral DNA can occur into many sites on target DNA with a wide variation in preference. One factor known to affect target site selection is integrase, the viral protein required for the integration reaction. In this study, assays that measure the distribution and frequency of retroviral DNA integration showed that purified integrases of human immunodeficiency virus type 1 (HIV-1) and feline immunodeficiency virus (FIV) had different patterns of target site usage. The integrase domain involved in target site selection was mapped by analyzing the integration pattern of chimeric proteins formed between HIV-1 and FIV integrases and of deletion variants of the two wild-type integrases. The results indicate that the domain responsible for target site selection resides in the central core region of integrase.