Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3A, also known as APOBEC3A, or A3A is a gene of the APOBEC3 family found in primates, including humans, and some other mammals. It is a single-domain DNA cytidine deaminase with antiviral effects. While other members of the family such as APOBEC3G are believed to act by editing ssDNA by removing an amino group from cytosine in DNA, introducing a cytosine to uracil change which can ultimately lead to a cytosine to thymine mutation, one study suggests that APOBEC3A can inhibit parvoviruses by another mechanism. The cellular function of APOBEC3A is likely to be the destruction of foreign DNA through extensive deamination of cytosine.
This gene is a member of the polynucleotide cytosine deaminase gene family. It is one of seven related genes or pseudogenes found in a cluster, thought to result from gene duplication, on chromosome 22. Members of the cluster encode proteins that are structurally and functionally related to the C to U RNA-editing cytidine deaminase APOBEC1. The APOBEC3 family of DNA editing enzymes are thought to be part of the innate immune system by restricting retroviruses, mobile genetic elements like retrotransposons and endogenous retroviruses. In addition, APOBEC3A is an important restrictive factor for HIV-1 and other retroviruses such as murine leukemia virus,
