Monoclonal antibody and siRNAs for topoisomerase I suppress telomerase activity.

Telomerase, a ribonucleoprotein enzyme, is a cellular RNA-dependent DNA polymerase that serves to maintain the tandem arrays of telomeric repeats at the eukaryotic chromosomal ends. We previously reported that topoisomerase I dissociates HIV-1 reverse transcriptase from genomic RNAs, and binding of topoisomerase I to RNA template regulates cDNA synthesis. We also found that a monoclonal antibody (MAb) against topoisomerase I, designated as MAb 1, suppresses the reverse transcription efficiency using a detergent-disrupted HIV-1 virion. In this study, we describe how MAb 1 suppresses telomerase activity in cellular lysates. In addition, siRNAs of topoisomerase I has attenuated telomerase activity in culture cells. These results suggest that topoisomerase I is involved in telomerase activity, as well as HIV-1 reverse transcription.