title: Reassessing the role of APOBEC3G in human immunodeficiency virus type 1 infection of quiescent CD4+ T-cells.
abstract: HIV-1 is restricted for infection of primary quiescent T-cells. After viral entry, reverse transcription is initiated but is not completed. Various hypotheses have been proposed for this cellular restriction including insufficient nucleotide pools and cellular factors, but none have been confirmed as the primary mechanism for restriction. A recent study by Chiu et al. implicates APOBEC3G, an anti-retroviral cytidine deaminase, as the cellular restriction factor. Here, we attempted to confirm these findings using the same strategy as reported by Chiu et al. of siRNA targeting knock-down of APOBEC3G expression. In contrast to the published study, our results do not support a role for APOBEC3G in restriction of HIV-1 in quiescent CD4+ T-cells. In our study, we tested the same siRNA as reported by Chiu et al. as well as two additional siRNAs targeting APOBEC3G, one of which showed 2-fold greater knock-down of APOBEC3G mRNA. However, none of the three siRNAs tested had a discernable effect on enhancing infection by HIV-1 in quiescent CD4+ T-cells. Therefore, we conclude that the primary mechanism of HIV-1 restriction in quiescent CD4+ T-cells remains to be elucidated.
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kamata
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nagaoka
authors.forename: Irvin S Y
authors.initials: IS
authors.lastname: Chen
mesh_terms: D000071480:APOBEC-3G Deaminase; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000821:virology*; D003564:Cytidine Deaminase / Q000235:genetics* / Q000378:metabolism; D005434:Flow Cytometry; D015658:HIV Infections / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000472:pathogenicity* / Q000502:physiology*; D006801:Humans; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D048348:Reverse Transcription; D014161:Transduction, Genetic
chemical_list: D034741:RNA, Small Interfering; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase