APOBEC3D and APOBEC3F Potently Promote HIV-1 Diversification and Evolution in Humanized Mouse Model

Several APOBEC3 proteins, particLilarly APOBEC3D, APOBEC3F, and APOBEC3G, induce G-to-A hypermutation in HIV-1 enome, and abrogate viral replication in experimental systems, but their relative contributions to controlling eplication and viral genetic variation in vivo have not been elucidated. On the other hand, an HIV-1-encoded protein, Vrf an degrade these APOBEC3 proteins via a ulpiquitiniproteasorne pathway. Although APOBEC3 proteins have been widely considered as potent restriction factors against HIV-1, it remains unclear which endogenous APOBEC3 protein(s) affect HIV-1 propagation in vivo. Here we use a humanized mouse model and HIV-1 with mutations in Vif motifs that are responsible for specific APOBEC3 interactions, DRMR/AAAA (4A) or YRHHY/AAAAA (5A), and demonstrate that endogenous APOBEC3D/F and APOBEC3G exert strong anti-HIV-1 activity in vivo. We also show that the growth kinetics of 4A HIV-1 negatively correlated with the expression level of APOBEC3F. Moreover, single genome sequencing analyses of viral RNA in plasma of nfected mice reveal that 4A HIV-1 is specifically and significantly diversified. Furthermore, a mutated virus that is capable of using both CCR5 and CXCR4 as entry coreceptor is specifically detected in 4A HIV-1-infected mice. Taken together, our ts demonstrate that APOBEC3D/F and APOBEC3G fundamentally work as restriction factors against HIV-1 in vivo but at the same time, that APOBEC3D and APOBEC3F are capable of promoting viral diversification and evolution in vivo.