The AID/APOBEC polynucleotide cytidine deaminases have historically been classified as either DNA mutators or RNA editors based on their first identified nucleic acid substrate preference. DNA mutators can generate functional diversity at antibody genes but also cause genomic instability in cancer. RNA editors can generate informational diversity in the transcriptome of innate immune cells, and of cancer cells. Members of both classes can act as antiviral restriction factors. Recent structural work has illuminated differences and similarities between AID/APOBEC enzymes that can catalyse DNA mutation, RNA editing or both, suggesting that the strict functional classification of members of this family should be reconsidered. As many of these enzymes have been employed for targeted genome (or transcriptome) editing, a more holistic understanding will help improve the design of therapeutically relevant programmable base editors.

AID/APOBEC 多核苷酸胞苷脱氨酶在历史上根据其首次鉴定的核酸底物偏好被分类为 DNA 突变体或 RNA 编辑器。DNA 突变体可以在抗体基因上产生功能多样性，但也会导致癌症的基因组不稳定性。RNA 编辑器可以在先天免疫细胞和癌细胞的转录组中产生信息多样性。这两个类别的成员都可以作为抗病毒限制因子。最近的结构研究阐明了可以催化 DNA 突变、RNA 编辑或两者兼有的 AID/APOBEC 酶之间的差异和相似之处，这表明应该重新考虑对该家族成员的严格功能分类。由于许多这些酶已被用于靶向基因组（或转录组）编辑，