HIV-1 Vif can directly inhibit apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G-mediated cytidine deamination by using a single amino acid interaction and without protein degradation.
The human apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G), also known as CEM-15, is a host-cell factor involved in innate resistance to retroviral infection. HIV-1 viral infectivity factor (Vif) protein was shown to protect the virus from APOBEC3G-mediated viral cDNA hypermutation. The mechanism proposed for protection of the virus by HIV-1 Vif is mediated by APOBEC3G degradation through ubiquitination and the proteasomal pathway. Here we show that in Escherichia coli the APOBEC3G-induced cytidine deamination is inhibited by expression of Vif without depletion of deaminase. Moreover, inhibition of deaminase-mediated bacterial hypermutation is dependent on a single amino acid substitution D128K that renders APOBEC3G resistant to Vif inhibition. This single amino acid was elegantly proven by other authors to determine species-specific sensitivity. Our results show that in bacteria this single amino acid substitution controls Vif-dependent blocking of APOBEC3G that is dependent on a strong protein interaction. The C-terminal region of Vif is responsible for this strong protein-protein interaction. In conclusion, our experiments suggest a complement to the model of Vif-induced degradation of APOBEC3G by bringing to relevance that deaminase inhibition can also result from a direct interaction with Vif protein.
Santa-Marta
Mariana
M
Unidade de Retrovirus e Infecçôes Associadas, Centro de Patogénese Molecular, Faculdade de Farmácia, Universidade de Lisboa, Av. das Forças Armadas, 1649-019 Lisboa, Portugal.
da Silva
Frederico Aires
FA
Fonseca
Ana Margarida
AM
Goncalves
Joao
J
D000071480:APOBEC-3G Deaminase; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001055:Apolipoproteins B / Q000235:genetics*; D001665:Binding Sites; D003564:Cytidine Deaminase / Q000378:metabolism*; D016346:Gene Products, vif / Q000494:pharmacology*; D015497:HIV-1 / Q000472:pathogenicity / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009700:Nucleoside Deaminases; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D017393:RNA Editing / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics*; D012097:Repressor Proteins; D054320:vif Gene Products, Human Immunodeficiency Virus
D001055:Apolipoproteins B; D016346:Gene Products, vif; D011506:Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D054320:vif Gene Products, Human Immunodeficiency Virus; D009700:Nucleoside Deaminases; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase