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Human topoisomerase I promotes HIV-1 proviral DNA synthesis: implications for the species specificity and cellular tropism of HIV-1 infection.

ABSTRACT: Although HIV type 1 (HIV-1) cannot efficiently replicate in simian cells, the mechanism(s) involved in the restriction of virus tropism remain unclear. To investigate this, we have focused on the identification of human cellular factors that can influence the infectivity of HIV-1 derived from African green monkey producer cells. Whereas the infectivity of HIV-1 derived from such cells was only 10-15% of that of human cell-derived virus, expression of human topoisomerase I in the African green monkey cells resulted in a 5-fold increase of the infectivity of progeny HIV-1 virions. Replacement of glutamate-236 and asparagine-237 of human topoisomerase I with the corresponding residues (aspartate and serine, respectively) of the African green monkey enzyme abolished this enhancement of HIV-1 infectivity. This positive effect of human topoisomerase I expression in the African green monkey producer cells seemed to result from the promotion of HIV-1 cDNA synthesis. Thus, human topoisomerase I plays an important role in HIV-1 replication and infectivity, and differences in the species specificity of HIV-1 infection can at least in part be attributed to differences in topoisomerase I activities.

SUBMITTER: Shoya Y

PROVIDER: S-EPMC166248 | biostudies-literature | 2003 Jul

REPOSITORIES: biostudies-literature

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Human topoisomerase I promotes HIV-1 proviral DNA synthesis: implications for the species specificity and cellular tropism of HIV-1 infection.

Shoya Yuko Y Tokunaga Kenzo K Sawa Hirofumi H Maeda Masae M Ueno Tomonori T Yoshikawa Tomoki T Hasegawa Hideki H Sata Tetsutaro T Kurata Takeshi T Hall William W WW Cullen Bryan R BR Takahashi Hidehiro H

Proceedings of the National Academy of Sciences of the United States of America 20030626 14

Although HIV type 1 (HIV-1) cannot efficiently replicate in simian cells, the mechanism(s) involved in the restriction of virus tropism remain unclear. To investigate this, we have focused on the identification of human cellular factors that can influence the infectivity of HIV-1 derived from African green monkey producer cells. Whereas the infectivity of HIV-1 derived from such cells was only 10-15% of that of human cell-derived virus, expression of human topoisomerase I in the African green mo ...[more]

PMID: 12829794

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Project description:The Maraviroc Switch collaborative study (MARCH) is a study in aviremic patients on stable antiretroviral therapy and utilizes population-based sequencing of proviral DNA to determine HIV tropism and susceptibility to maraviroc. An external quality assessment (EQA) program was implemented to ensure competency in assessing the tropism of clinical samples conducted by MARCH laboratories (n = 14). The MARCH EQA has three prestudy phases assessing V3 loop sequencing and tropism determination using the bioinformatic algorithm geno2pheno, which generates a false-positive rate (FPR). DNA sequences with low FPRs are more likely to be from CXCR4-using (X4) viruses. Phase 1 of the EQA involved chromatogram interpretation. Phases 2, 2/3, and 3 involved patient and clonal samples. Clinical samples used in these phases were from treatment-experienced HIV-infected volunteers; 18/20 had viral loads of <50 copies/ml, and 10/15 were CXCR4-tropic on prior phenotyping. All samples were tested in triplicate, and any replicate with a geno2pheno FPR of <10% was designated X4. Performance was deemed adequate if ?2 R5 and ?1 X4 specimens were miscalled. For several clinical samples in the EQA, triplicate testing revealed marked DNA variability (FPR range, 0 to 96.7%). Therefore, a consensus-based approach was employed for each sample, i.e., a median FPR across laboratories was used to define sample tropism. Further sequencing analysis showed mixed viral populations in the clinical samples, explaining the differences in tropism predictions. All laboratories passed the EQA after achieving predefined competence thresholds in either of the phase 2 rounds. The use of clinical samples from patients resembling those who were likely to be screened in the MARCH, coupled with triplicate testing, revealed inherent DNA variability that might have been missed if single or duplicate testing and/or clonal samples alone were used. These data highlight the importance of intensive EQA of tropism laboratories before embarking on clinical studies. (This study has been registered at ClinicalTrials.gov under registration no. NCT01384682 [http://www.clinicaltrials.gov/ct2/show/study/NCT01384682?term=NCT01384682&rank=1].).

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Dataset Information

Human topoisomerase I promotes HIV-1 proviral DNA synthesis: implications for the species specificity and cellular tropism of HIV-1 infection.

Publications

Human topoisomerase I promotes HIV-1 proviral DNA synthesis: implications for the species specificity and cellular tropism of HIV-1 infection.

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