title: Mutational comparison of the single-domained APOBEC3C and double-domained APOBEC3F/G anti-retroviral cytidine deaminases provides insight into their DNA target site specificities.
abstract: Human APOBEC3F and APOBEC3G are double-domained deaminases that can catalyze dC-->dU deamination in HIV-1 and MLV retroviral DNA replication intermediates, targeting T-C or C-C dinucleotides, respectively. HIV-1 antagonizes their action through its vif gene product, which has been shown (at least in the case of APOBEC3G) to interact with the N-terminal domain of the deaminase, triggering its degradation. Here, we compare APOBEC3F and APOBEC3G to APOBEC3C, a single-domained deaminase that can also act on both HIV-1 and MLV. We find that whereas APOBEC3C contains all the information necessary for both Vif-binding and cytidine deaminase activity in a single domain, it is the C-terminal domain of APOBEC3F and APOBEC3G that confer their target site specificity for cytidine deamination. We have exploited the fact that APOBEC3C, whilst highly homologous to the C-terminal domain of APOBEC3F, exhibits a distinct target site specificity (preferring Y-C dinucleotides) in order to identify residues in APOBEC3F that might affect its target site specificity. We find that this specificity can be altered by single amino acid substitutions at several distinct positions, suggesting that the strong dependence of APOBEC3-mediated deoxycytidine deamination on the 5'-flanking nucleotide is sensitive to relatively subtle changes in the APOBEC3 structure. The approach has allowed the isolation of APOBEC3 DNA mutators that exhibit novel target site preferences.
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Langlois
authors.forename: Rupert C L
authors.initials: RC
authors.lastname: Beale
authors.forename: Silvestro G
authors.initials: SG
authors.lastname: Conticello
authors.forename: Michael S
authors.initials: MS
authors.lastname: Neuberger
mesh_terms: D000071480:APOBEC-3G Deaminase; D019943:Amino Acid Substitution; D044966:Anti-Retroviral Agents / Q000737:chemistry* / Q000494:pharmacology*; D003564:Cytidine Deaminase / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D043525:Cytosine Deaminase / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D004252:DNA Mutational Analysis; D004279:DNA, Viral / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009052:Leukemia Virus, Murine / Q000187:drug effects / Q000235:genetics; D009700:Nucleoside Deaminases; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012097:Repressor Proteins; D013379:Substrate Specificity
chemical_list: D044966:Anti-Retroviral Agents; D004279:DNA, Viral; D011506:Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D009700:Nucleoside Deaminases; C492906:APOBEC3F protein, human; D043525:Cytosine Deaminase; D000071480:APOBEC-3G Deaminase; C495795:APOBEC3C protein, human; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase