Effects of nucleoside analogs on native and site-directed mutants of HTLV type 1 reverse transcriptase

A bacterial assay was developed for testing HTLV-1 reverse transcriptase se nsitivity to common nucleoside analog inhibitors in an Escherichia coli str ain characterized by a temperature sensitive PolI/RecA deletion phenotype. This genetic complementation assay exploits the ability of HTLV-1 reverse t ranscriptase to functionally replace these missing activities at nonpermiss ive temperatures. The four inhibitors tested, dideoxyinosine, dideoxyadenos ine, deoxythymidine, and didehydrodeoxythymidine are well-known inhibitors of HIV reverse transcriptase. All except dideoxyadenosine showed a strong a ctivity against HTLV-1 reverse transcriptase with ICS, in the nanomolar ran ge. Sequence alignments were used to identify amino acid residues in HTLV-I reverse transcriptase, which correspond to those identified as important f or drug-resistance in HIV reverse transcriptase. Mutations of some of these HTLV-I residues altered the ICS, for the inhibitors as expected, which sug gests that these amino acids have a function in HTLV-1 reverse transcriptas e similar to that of their homologs in HIV reverse transcriptase, (C) 2000 Academic Press.