APOBEC3G Restricts HIV-1 to a Greater Extent than APOBEC3F and APOBEC3DE in Human Primary CD4+ T Cells and Macrophages

C Chaipan, JL Smith, WS Hu, VK Pathak - Journal of virology, 2013 - Am Soc Microbiol
C Chaipan, JL Smith, WS Hu, VK Pathak
Journal of virology, 2013Am Soc Microbiol
ABSTRACT APOBEC3 proteins inhibit HIV-1 replication in experimental systems and induce
hypermutation in infected patients; however, the relative contributions of several APOBEC3
proteins to restriction of HIV-1 replication in the absence of the viral Vif protein in human
primary CD4+ T cells and macrophages are unknown. We observed significant inhibition of
HIV-1Δ vif produced in 293T cells in the presence of APOBEC3DE (A3DE), APOBEC3F
(A3F), APOBEC3G (A3G), and APOBEC3H haplotype II (A3H HapII) but not APOBEC3B …
Abstract
APOBEC3 proteins inhibit HIV-1 replication in experimental systems and induce hypermutation in infected patients; however, the relative contributions of several APOBEC3 proteins to restriction of HIV-1 replication in the absence of the viral Vif protein in human primary CD4+ T cells and macrophages are unknown. We observed significant inhibition of HIV-1Δvif produced in 293T cells in the presence of APOBEC3DE (A3DE), APOBEC3F (A3F), APOBEC3G (A3G), and APOBEC3H haplotype II (A3H HapII) but not APOBEC3B (A3B), APOBEC3C (A3C), or APOBEC3H haplotype I (A3H HapI). Our previous studies showed that Vif amino acids Y40RHHY44 are important for inducing proteasomal degradation of A3G, whereas amino acids 14DRMR17 are important for degradation of A3F and A3DE. Here, we introduced substitution mutations of 40YRHHY44 and 14DRMR17 in replication-competent HIV-1 to generate vif mutants NL4-3 YRHHY>A5 and NL4-3 DRMR>A4 to compare the antiviral activity of A3G to the combined antiviral activity of A3F and A3DE in activated CD4+ T cells and macrophages. During the first 15 days (round 1), in which multiple cycles of viral replication occurred, both the NL4-3 YRHHY>A5 and NL4-3 DRMR>A4 mutants replicated in activated CD4+ T cells and macrophages, and only the NL4-3 YRHHY>A5 mutant showed a 2- to 4-day delay in replication compared to the wild type. During the subsequent 27 days (round 2) of cultures initiated with peak virus obtained from round 1, the NL4-3 YRHHY>A5 mutant exhibited a longer, 8- to 10-day delay and the NL4-3 DRMR>A4 mutant exhibited a 2- to 6-day delay in replication compared to the wild type. The NL4-3 YRHHY>A5 and NL4-3 DRMR>A4 mutant proviruses displayed G-to-A hypermutations primarily in GG and GA dinucleotides as expected of A3G- and A3F- or A3DE-mediated deamination, respectively. We conclude that A3G exerts a greater restriction effect on HIV-1 than A3F and A3DE.
American Society for Microbiology