Monoclonal antibodies against topoisomerase I suppressed DNA relaxation and HIV-1 cDNA synthesis.

Human immunodeficiency virus type 1 (HIV-1) virion is known to carry a number of cellular components including cellular topoisomerase I. Previously, we have demonstrated that topoisomerase I enhances HIV-1 cDNA synthesis in reverse transcription (RT) assays in vitro. In the present study, we have produced six monoclonal antibodies (MAbs) against human topoisomerase I. The MAbs suppressed nicking/closing of supercoiled DNA and cDNA synthesis in an endogenous reverse transcription (ERT) assay using a detergent-disrupted HIV-1 virion. Thus, the results suggest that topoisomerase I plays an important role in RNA-directed DNA polymerization.