title: Functional analysis of the two cytidine deaminase domains in APOBEC3G.
abstract: Human APOBEC3G (hA3G), a cytidine deaminase with two cytidine deaminase domains (CDs), has been identified as an anti-HIV-1 host factor. Although the two CDs of hA3G have been extensively characterized, there is still debate on the role of the CDs in the biological function of hA3G. In this work, we constructed three hA3G mutants CD1-1, CD2-2 and CD2-1, which contain duplicate CD1 domain, duplicate CD2 domain and position switched CD domain respectively, and investigated the effect of CD domain replacement or switch upon virion encapsidation, Vif-mediated degradation, deamination and antiviral activity of hA3G. The results showed that the two CD domains were functionally equivalent in virion encapsidation and the interaction with HIV-1 Vif of hA3G, whereas CD domain switch or replacement greatly affected the sensitivity to Vif induced degradation, editing and antiviral activity of hA3G. Although the CD2 domain was shown to possess the deamination activity, CD2-2 incorporated efficiently into HIV-1 was unable to mutate viral cDNA, suggesting that CD1 also involved in the enzymatic function. Interestingly, CD2-1 retained considerable deamination activity with a different sequence preference. Taken together, our results suggest that CD domain may play a structural role in virion encapsidation and Vif-mediated degradation of hA3G, and coordination of the two CD domains is required for its editing and antiviral activity.
authors.affiliation: Institute of Medicinal Biotechnology, Beijing, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jinming
authors.initials: J
authors.lastname: Zhou
authors.forename: Xiao
authors.initials: X
authors.lastname: Yin
authors.forename: Congjie
authors.initials: C
authors.lastname: Zhai
authors.forename: Xuefu
authors.initials: X
authors.lastname: You
authors.forename: Liyan
authors.initials: L
authors.lastname: Yu
authors.forename: Fei
authors.initials: F
authors.lastname: Guo
authors.forename: Lixun
authors.initials: L
authors.lastname: Zhao
authors.forename: Zelin
authors.initials: Z
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Zeng
authors.forename: Shan
authors.initials: S
authors.lastname: Cen
mesh_terms: D000071480:APOBEC-3G Deaminase; D000595:Amino Acid Sequence; D002460:Cell Line; D003564:Cytidine Deaminase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015658:HIV Infections / Q000201:enzymology* / Q000235:genetics / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D016415:Sequence Alignment; D054320:vif Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism
chemical_list: D054320:vif Gene Products, Human Immunodeficiency Virus; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase