This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by White, K. L. Articles by Miller, M. D. Search for Related Content PubMed PubMed Citation Articles by White, K. L. Articles by Miller, M. D.

Molecular Mechanisms of Tenofovir Resistance Conferred by Human Immunodeficiency Virus Type 1 Reverse Transcriptase Containing a Diserine Insertion after Residue 69 and Multiple Thymidine Analog-Associated Mutations

Gilead Sciences, Foster City, California, 94404,¹ ViroLogic, Inc., South San Francisco, California, 94080²

Received 29 May 2003/ Returned for modification 7 August 2003/ Accepted 13 November 2003

Two amino acids inserted between residues 69 and 70 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) are rare mutations that may develop in viruses containing multiple thymidine analog (zidovudine [AZT], stavudine)-associated mutations and that confer high-level resistance to all currently approved chain-terminating nucleoside and nucleotide RT inhibitors (NRTIs). The two known mechanisms of resistance to NRTIs are decreased incorporation and increased excision. The mechanism used by RT insertion mutants has not been described for tenofovir (TFV), a recently approved agent in this class. A patient-derived HIV-1 strain (strain FS-SSS) that contained an insertion mutation in a background of additional resistance mutations M41L, L74V, L210W, and T215Y was obtained. A second virus (strain FS) was derived from FS-SSS. In strain FS the insertion and T69S were reverted but the other resistance mutations were retained. The FS virus showed strong resistance to AZT but low-level changes in susceptibilities to other NRTIs and TFV. The FS-SSS virus showed reduced susceptibilities to all NRTIs including TFV. Steady-state kinetics demonstrated that the relative binding or incorporation of TFV was slightly decreased for FS-SSS RT compared to those for wild-type RT. However, significant ATP-mediated excision of TFV was detected for both mutant RT enzymes and followed the order FS-SSS RT > FS RT > wild-type RT. The presence of physiological concentrations of the +1 nucleotide inhibited TFV excision by the wild-type RT and slightly inhibited excision by the FS RT, whereas the level of excision by the FS-SSS RT remained high. Computer modeling suggests that the increased mobility of the ß3-ß4 loop may contribute to the high-level and broad NRTI resistance caused by the T69 insertion mutation.

This article has been cited by other articles:

• Marchand, B., White, K. L., Ly, J. K., Margot, N. A., Wang, R., McDermott, M., Miller, M. D., Gotte, M. (2007). Effects of the Translocation Status of Human Immunodeficiency Virus Type 1 Reverse Transcriptase on the Efficiency of Excision of Tenofovir. Antimicrob. Agents Chemother. 51: 2911-2919 [Abstract] [Full Text]  
• Margot, N. A., Waters, J. M., Miller, M. D. (2006). In Vitro Human Immunodeficiency Virus Type 1 Resistance Selections with Combinations of Tenofovir and Emtricitabine or Abacavir and Lamivudine. Antimicrob. Agents Chemother. 50: 4087-4095 [Abstract] [Full Text]  
• Winters, M. A., Merigan, T. C. (2005). Insertions in the Human Immunodeficiency Virus Type 1 Protease and Reverse Transcriptase Genes: Clinical Impact and Molecular Mechanisms. Antimicrob. Agents Chemother. 49: 2575-2582 [Full Text]  
• Boyer, P. L., Imamichi, T., Sarafianos, S. G., Arnold, E., Hughes, S. H. (2004). Effects of the {Delta}67 Complex of Mutations in Human Immunodeficiency Virus Type 1 Reverse Transcriptase on Nucleoside Analog Excision. J. Virol. 78: 9987-9997 [Abstract] [Full Text]  
• Wang, L. Z., Kenyon, G. L., Johnson, K. A. (2004). Novel Mechanism of Inhibition of HIV-1 Reverse Transcriptase by a New Non-nucleoside Analog, KM-1. J. Biol. Chem. 279: 38424-38432 [Abstract] [Full Text]  
• Matamoros, T., Franco, S., Vazquez-Alvarez, B. M., Mas, A., Martinez, M. A., Menendez-Arias, L. (2004). Molecular Determinants of Multi-nucleoside Analogue Resistance in HIV-1 Reverse Transcriptases Containing a Dipeptide Insertion in the Fingers Subdomain: EFFECT OF MUTATIONS D67N AND T215Y ON REMOVAL OF THYMIDINE NUCLEOTIDE ANALOGUES FROM BLOCKED DNA PRIMERS. J. Biol. Chem. 279: 24569-24577 [Abstract] [Full Text]