Mol Biol Evol. 2011 Mar;28(3):1125-9. doi: 10.1093/molbev/msq338. Epub 2010 Dec 15.
The Activation Induced Deaminase (AID)/APOBEC family of deaminases targeting nucleic acids arose at the beginning of the vertebrate radiation and further expanded in mammals. Following an analysis of the available genomic data, we report the identification of the APOBEC5, a novel group of paralogues in tetrapods. Moreover, we find bona fide homologues of Apolipoprotein B Editing Complex 1 (APOBEC1) in the genomes of anole lizard and zebra finch, thus implying its appearance prior to the divergence of the amniotes. apolipoprotein B editing complex 1 (APOBEC1), in contrast with other AID/APOBECs acting on DNA, is an RNA-editing enzyme that targets the transcript of Apolipoprotein B (ApoB), thereby causing the translation of a truncated form of the protein. 3'RACE experiments reveal a lizard APOBEC1-like molecule lacking a C-terminal region important for mammalian ApoB RNA editing. This observation pairs with the finding that lizard ApoB is not deaminated at the region corresponding to the mammalian site of editing. Similar to mammalian APOBEC1, the lizard protein is able to deaminate DNA in bacteria and shows a conserved mutational context. Although not precluding the possibility that lizard APOBEC1 acts on unknown mRNA targets, these findings suggest that its ability to target DNA predates its role in RNA editing.
激活诱导脱氨酶（AID）/APOBEC 家族的脱氨酶靶向核酸，起源于脊椎动物辐射的早期，并在哺乳动物中进一步扩展。在分析了现有基因组数据之后，我们鉴定出了 APOBEC5，这是四足动物中新的同源基因家族。此外，我们在蜥蜴和斑胸草雀的基因组中发现了载脂蛋白 B 编辑复合物 1（APOBEC1）的真正同源物，这表明它出现在羊膜动物分化之前。载脂蛋白 B 编辑复合物 1（APOBEC1）与作用于 DNA 的其他 AID/APOBEC 不同，它是一种 RNA 编辑酶，靶向载脂蛋白 B（ApoB）的转录本，从而导致该蛋白的截断形式的翻译。3'RACE 实验揭示了一种缺乏对哺乳动物 ApoB RNA 编辑至关重要的 C 末端区域的蜥蜴 APOBEC1 样分子。这一观察结果与蜥蜴 ApoB 未在与哺乳动物编辑位点相对应的区域脱氨酶的发现相吻合。与哺乳动物 APOBEC1 相似，蜥蜴蛋白能够在细菌中脱氨，并显示出保守的突变背景。尽管不能排除蜥蜴 APOBEC1 作用于未知 mRNA 靶标的可能性，但这些发现表明，其靶向 DNA 的能力早于其在 RNA 编辑中的作用。
