Function
Activation-induced cytidine deaminase (AID) is a single-stranded DNA-specific cytidine deaminase that plays a crucial role in the adaptive immune system. It is involved in somatic hypermutation (SHM), gene conversion, and class-switch recombination (CSR) in B-lymphocytes. AID deaminates cytosine to uracil during transcription of immunoglobulin variable (V) and switch (S) region DNA, contributing to the generation of antibody diversity and affinity maturation. AID's function is essential for several critical steps in B-cell terminal differentiation, ensuring efficient antibody responses. Additionally, AID may participate in DNA demethylation, suggesting a potential role in epigenetic regulation of gene expression.