PCR Amplification and Cloning of Virtually Full-Length HIV-1 Provirus

Molecular analyses of HIV-1 variation, and its impact on the biological properties of the virus have by necessity been restricted by the scarcity of cloned proviruses. Only a handful of full-length clones exist (1), and of these, even a smaller fraction are infectious upon transfection into cell lines. Furthermore, the available infectious clones only represent subtypes B and D (1). The main reasons for the lack of infectious clones are related to the relatively low copy number of proviral DNA especially in primary cultures (8).