DNA Dc->Du-Editing Enzyme APOBEC-3a (APOBEC3A) Human Recombinant Protein

This gene is a member of the cytidine 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 protein encoded by this gene lacks the zinc binding activity of other family members. The protein plays a role in immunity, by restricting transmission of foreign DNA such as viruses. One mechanism of foreign DNA restriction is deamination of foreign double-stranded DNA cytidines to uridines, which leads to DNA degradation. However, other mechanisms are also thought to be involved, as anti-viral effect is not dependent on deaminase activity. The protein encoded by this gene is the same as that encoded by APOBEC3A; however, this gene is a hybrid gene that results from the deletion of approximately 29.5 kb of sequence between the APOBEC3A gene and the adjacent gene APOBEC3B. The breakpoints of the deletion are within the two genes, so the deletion hybrid is predicted to have the promoter and coding region of APOBEC3A, but the 3' UTR of APOBEC3B. [provided by RefSeq, Jul 2012]

APOBEC3A: a single-stranded DNA cytidine deaminase involved in foreign DNA clearance with restriction activity against viruses, foreign DNA and mobility of retrotransposons. Exhibits antiviral activity against adeno-associated virus (AAV) and human T-cell leukemia virus type 1 (HTLV-1) and may inhibit the mobility of LTR and non-LTR retrotransposons. Selectively targets single-stranded DNA and can deaminate both methylcytosine and cytosine in foreign DNA. Can induce somatic C-to-U hypermutation in nuclear and mitochondrial DNA. May also play a role in the epigenetic regulation of gene expression through the process of active DNA demethylation. Interacts with AGO2. Interacts with TRIB3. Expressed in peripheral leukocytes with higher expression in CD14-positive phagocytic cells. Highly expressed in keratinocytes and in periphery blood monocytes. Also detected in non-lymphoid tissues including lung and adipose tissues. Found at high levels in colorectal adenocarcinoma, Burkitt's lymphoma and chronic myelogenous leukemia. Up-regulated by interferon and CpG single-stranded DNA (at protein level). Belongs to the cytidine and deoxycytidylate deaminase family. 2 isoforms of the human protein are produced by alternative initiation.

Protein type: EC 3.5.4.-; Hydrolase

Chromosomal Location of Human Ortholog: 22q13.1-q13.2

Cellular Component: cytoplasm; nucleoplasm; nucleus

Molecular Function: cytidine deaminase activity; deoxycytidine deaminase activity; protein binding; zinc ion binding

Biological Process: cytidine deamination; defense response to virus; innate immune response; negative regulation of viral genome replication