Assessment of the Role of the Central DNA Flap in Human Immunodeficiency Virus Type 1 Replication by Using a Single-Cycle Replication System

Abstract

In this study, reverse transcriptase (RT)- and integrase (IN)-defective human immunodeficiency virus type 1 (HIV-1) was transcomplemented with Vpr-RT-IN fusion proteins to delineate pol sequences important for HIV-1 replication. Our results reveal that a 194-bp sequence encompassing the 3′end of the IN gene and containing the central DNA flap is necessary and sufficient for efficient HIV-1 single-cycle replication in dividing and nondividing cells. Furthermore, we show that the central DNA flap enhances HIV-1 single-round replication by five- to sevenfold, primarily by facilitating nuclear import of proviral DNA. In agreement with previous reports, our data support a functional role of the central DNA flap during the early stages of HIV-1 infection.