This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Delviks-Frankenberry, K. A.
Right arrow Articles by Pathak, V. K.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Delviks-Frankenberry, K. A.
Right arrow Articles by Pathak, V. K.

 Previous Article  |  Next Article 

Journal of Virology, September 2009, p. 8502-8513, Vol. 83, No. 17
0022-538X/09/$08.00+0     doi:10.1128/JVI.00859-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Subtype-Specific Differences in the Human Immunodeficiency Virus Type 1 Reverse Transcriptase Connection Subdomain of CRF01_AE Are Associated with Higher Levels of Resistance to 3'-Azido-3'-Deoxythymidine {triangledown}

Krista A. Delviks-Frankenberry,1 Galina N. Nikolenko,1 Frank Maldarelli,2 Saiki Hase,3 Yutaka Takebe,3 and Vinay K. Pathak1*

Viral Mutation Section,1 Host-Virus Interaction Branch, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, Maryland,2 Laboratory of Molecular Virology and Epidemiology, AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan3

Received 28 April 2009/ Accepted 17 June 2009

We previously shown that mutations in the connection (CN) subdomain of human immunodeficiency virus type 1 (HIV-1) subtype B reverse transcriptase (RT) increase 3'-azido-3'-deoxythymidine (AZT) resistance in the context of thymidine analog mutations (TAMs) by affecting the balance between polymerization and RNase H activity. To determine whether this balance affects drug resistance in other HIV-1 subtypes, recombinant subtype CRF01_AE was analyzed. Interestingly, CRF01_AE containing TAMs exhibited 64-fold higher AZT resistance relative to wild-type B, whereas AZT resistance of subtype B containing the same TAMs was 13-fold higher, which in turn correlated with higher levels of AZT-monophosphate (AZTMP) excision on both RNA and DNA templates. The high level of AZT resistance exhibited by CRF01_AE was primarily associated with the T400 residue in wild-type subtype AE CN subdomain. An A400T substitution in subtype B enhanced AZT resistance, increased AZTMP excision on both RNA and DNA templates, and reduced RNase H cleavage. Replacing the T400 residue in CRF01_AE with alanine restored AZT sensitivity and reduced AZTMP excision on both RNA and DNA templates, suggesting that the T400 residue increases AZT resistance in CRF01_AE at least in part by directly increasing the efficiency of AZTMP excision. These results show for the first time that CRF01_AE exhibits higher levels of AZT resistance in the presence of TAMs and that this resistance is primarily associated with T400. Our results also show that mixing the RT polymerase, CN, and RNase H domains from different subtypes can underestimate AZT resistance levels, and they emphasize the need to develop subtype-specific genotypic and phenotypic assays to provide more accurate estimates of clinical drug resistance.

* Corresponding author. Mailing address: HIV Drug Resistance Program, Building 535, Room 334, National Cancer Institute—Frederick, Frederick, MD 21702. Phone: (301) 846-1710. Fax: (301) 846-6013. E-mail: vpathak{at}ncifcrf.gov

{triangledown} Published ahead of print on 24 June 2009.

Journal of Virology, September 2009, p. 8502-8513, Vol. 83, No. 17
0022-538X/09/$08.00+0     doi:10.1128/JVI.00859-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»