DNA dC->dU-editing enzyme APOBEC-3C is a protein that in humans is encoded by the APOBEC3C gene. [3] [4]
A3C belong to the A3 family of cytidine deaminases that act as restriction factors against diverse retroviruses. A3C was reported to inhibit simian immunodeficiency deficiency virus potently rather than HIV-1, in absence of viral infectivity factor, Vif. [5] Enhancing A3C's catalytic activity had only a marginal effect on HIV-1 replication (in absence of Vif), the counteractive viral mechanism is unclear. [6] A3C was also shown to inhibit other viruses. [7] [8] [9] [10] [11]
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. Conversely, A3 proteins enzymatically convert cytidine to uridine present in the single stranded DNA. [12] [13] [14] [15] [16] Two residues in loop 1 of A3C were demonstrated to determine its antiviral activity against HIV-1. [17]
The crystal structure of A3C suggests a putative HIV-1 vif binding region. [18] [19] A3C was found to inhibit LINE-1 elements by directly interacting with ORF1p proteins, in a deaminase-independent manner. [20]