Figure 5
Anti-SRV-4 ability of human APOBEC3 proteins.
(a) Dose-dependent anti-SRV-4 ability of human APOBEC3F and APOBEC3G. 293T cells were cotransfected with pSR415 (1 μg), pSRV4ψluc (1 μg) and flag-tagged APOBEC3G (blue) or APOBEC3F (red) expression plasmids (25, 50, 100, or 200 ng) and the infectivity of the released virions in the culture supernatant was measured as described in Methods. The infectivity is shown as the percentage of the value of APOBEC3-untransfected cells. (b,c) Western blotting. 293T cells were cotransfected with pSR415 (1 μg), pSRV4ψluc (1 μg) and flag-tagged APOBEC3G (blue) or APOBEC3F (red) expression plasmids (200 ng). The expression levels of viral proteins (Gag and CA) and flag-tagged APOBEC3s in the transfected cells, the amount of released virion in the culture supernatant (CA and TM) and the amount of APOBEC3 in the released virion was assessed by Western blotting. The input of cell lysate was standardized to α-tubulin (TUBA) and representative results are shown in b. The amount of APOBEC3s in the released virion was quantified as described in Methods and the summarized data of the 6 independent experiments are shown in c. (d) Deaminase-dependent anti-SRV-4 ability of human APOBEC3F and APOBEC3G. 293T cells were cotransfected with pSR415 (1 μg), pSRV4ψluc (1 μg) and flag-tagged plasmid (200 ng) expressing wild-type (WT) APOBEC3G, APOBEC3G E259Q, WT APOBEC3F, or APOBEC3F E251Q. The infectivity of the released virions in the culture supernatant was measured as described in Methods and is shown as the percentage of the value of APOBEC3-untransfected cells. In a and d, the assays were performed in triplicate. The statistical difference is determined by Student’s t test and statistically significant difference (P < 0.05) against no APOBEC3 is indicated by asterisks. Error bars represent SDs. In b, blots have been cropped; full uncropped blots are available as Supplementary Figure 4.
