DNA dC->dU-editing enzyme APOBEC-3A; phorbolin-1 (APOBEC3A)

Function

• single-stranded DNA cytidine deaminase involved in foreign DNA clearance
• may trigger C-to-U hypermutation in exogenous DNA leading to its degradation
• provides cellular innate resistance to a specific panel of genetic invaders including endogenous retroelements & a subset of viruses
• may have a preference for cytidines in a C-C sequence context
• may also play a role in the epigenetic regulation of gene expression through the process of active DNA demethylation

cytidine + H2O = uridine + NH3

Cofactor: Zn+2 (putative)

Structure

• belongs to the cytidine & deoxycytidylate deaminase family

Compartment

• nucleus, cytoplasm

Alternative initiation

Named isoforms=2

Expression

• expressed in peripheral blood leukocytes
  • higher expression in CD14-positive phagocytic cells
• also detected in non-lymphoid tissues including lung & adipose tissues
• also detected in keratinocytes
• up-regulated by interferon & CpG single-stranded DNA (at protein level)

Notes

• one of 7 related genes or pseudogenes found in a cluster, thought to result from gene duplication, on chromosome 22

More general terms

• DNA dC->dU-editing enzyme (phorbolin)
• nuclear protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=200315
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:200315
• OMIM: https://mirror.omim.org/entry/607109
• UniProt: http://www.uniprot.org/uniprot/P31941.html