title: Effects of dipeptide insertions between codons 69 and 70 of human immunodeficiency virus type 1 reverse transcriptase on primer unblocking, deoxynucleoside triphosphate inhibition, and DNA chain elongation.
abstract: Finger insertion mutations of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) (T69S mutations followed by various dipeptide insertions) have a multinucleoside resistance phenotype that can be explained by decreased sensitivity to deoxynucleoside triphosphate (dNTP) inhibition of the nucleotide-dependent unblocking activity of RT. We show that RTs with SG or AG (but not SS) insertions have three- to fourfold-increased unblocking activity and that all three finger insertion mutations have threefold-decreased sensitivity to dNTP inhibition. The additional presence of M41L and T215Y mutations increased unblocking activity for all three insertions, greatly reduced the sensitivity to dNTP inhibition, and resulted in defects in in vitro DNA chain elongation. The DNA chain elongation defects were partially repaired by additional mutations at positions 210, 211, and 214. These results suggest that structural communication between the regions of RT defined by these mutations plays a role in the multinucleoside resistance phenotype.
authors.affiliation: University of Miami, School of Medicine, Miami, Florida 33101-6129, USA.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Meyer
authors.forename: Johan
authors.initials: J
authors.lastname: Lennerstrand
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Matsuura
authors.forename: Brendan A
authors.initials: BA
authors.lastname: Larder
authors.forename: Walter A
authors.initials: WA
authors.lastname: Scott
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D003062:Codon / Q000235:genetics*; D017931:DNA Primers; D004279:DNA, Viral / Q000378:metabolism; D015224:Dideoxynucleosides / Q000494:pharmacology*; D015226:Dinucleoside Phosphates / Q000494:pharmacology; D004151:Dipeptides / Q000737:chemistry / Q000235:genetics*; D024921:Drug Resistance, Multiple, Viral; D054303:HIV Reverse Transcriptase / Q000737:chemistry / Q000187:drug effects / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D009154:Mutation; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology; D015215:Zidovudine / Q000494:pharmacology
chemical_list: D003062:Codon; D017931:DNA Primers; D004279:DNA, Viral; D015224:Dideoxynucleosides; D015226:Dinucleoside Phosphates; D004151:Dipeptides; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine; D000255:Adenosine Triphosphate; D054303:HIV Reverse Transcriptase