TY - JOUR
T1 - Restricted 5′-end gap repair of HIV-1 integration due to limited cellular dNTP concentrations in human primary macrophages
AU - Van Cor-Hosmer, Sarah K.
AU - Kim, Dong Hyun
AU - Daly, Michele B.
AU - Daddacha, Waaqo
AU - Kim, Baek
PY - 2013/11/15
Y1 - 2013/11/15
N2 - HIV-1 proviralDNAintegration into host chromosomalDNA is only partially completed by the viral integrase, leaving two single-stranded DNA gaps with 5′-end mismatched viral DNA flaps. It has been inferred that these gaps are repaired by the cellular DNA repair machinery. Here, we investigated the efficiency of gap repair at integration sites in different HIV-1 target cell types. First, we found that the general gap repair machinery in macrophages was attenuated compared with that in dividing CD4+ T cells. In fact, the repair in macrophages was heavily reliant upon host DNA polymerase β (Pol β). Second, we tested whether the poor dNTP availability found in macrophages is responsible for the delayed HIV-1 proviral DNA integration in this cell type because the Km value of Pol β is much higher than the dNTP concentrations found in macrophages. Indeed, with the use of a modified quantitative AluI PCR assay, we demonstrated that the elevation of cellular dNTP concentrations accelerated DNA gap repair in macrophages at HIV-1 proviral DNA integration sites. Finally, we found that human monocytes, which are resistant to HIV-1 infection, exhibited severely restricted gap repair capacity due not only to the very low levels of dNTPs detected but also to the significantly reduced expression of Pol β. Taken together, these results suggest that the low dNTP concentrations found in macrophages and monocytes can restrict the repair steps necessary for HIV-1 integration.
AB - HIV-1 proviralDNAintegration into host chromosomalDNA is only partially completed by the viral integrase, leaving two single-stranded DNA gaps with 5′-end mismatched viral DNA flaps. It has been inferred that these gaps are repaired by the cellular DNA repair machinery. Here, we investigated the efficiency of gap repair at integration sites in different HIV-1 target cell types. First, we found that the general gap repair machinery in macrophages was attenuated compared with that in dividing CD4+ T cells. In fact, the repair in macrophages was heavily reliant upon host DNA polymerase β (Pol β). Second, we tested whether the poor dNTP availability found in macrophages is responsible for the delayed HIV-1 proviral DNA integration in this cell type because the Km value of Pol β is much higher than the dNTP concentrations found in macrophages. Indeed, with the use of a modified quantitative AluI PCR assay, we demonstrated that the elevation of cellular dNTP concentrations accelerated DNA gap repair in macrophages at HIV-1 proviral DNA integration sites. Finally, we found that human monocytes, which are resistant to HIV-1 infection, exhibited severely restricted gap repair capacity due not only to the very low levels of dNTPs detected but also to the significantly reduced expression of Pol β. Taken together, these results suggest that the low dNTP concentrations found in macrophages and monocytes can restrict the repair steps necessary for HIV-1 integration.
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U2 - 10.1074/jbc.M113.486787
DO - 10.1074/jbc.M113.486787
M3 - Article
C2 - 24097986
AN - SCOPUS:84887835426
SN - 0021-9258
VL - 288
SP - 33253
EP - 33262
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 46
ER -