Section 10
Chapter 9,761

Activation-induced cytidine deaminase shuttles between nucleus and cytoplasm like apolipoprotein B mRNA editing catalytic polypeptide 1

Ito, S.; Nagaoka, H.; Shinkura, R.; Begum, N.; Muramatsu, M.; Nakata, M.; Honjo, T.

Proceedings of the National Academy of Sciences of the United States of America 101(7): 1975-1980


ISSN/ISBN: 0027-8424
PMID: 14769937
DOI: 10.1073/pnas.0307335101
Accession: 009760380

Activation-induced cytidine deaminase (AID) is a molecule central to initiating class switch recombination, somatic hypermutation, and gene conversion of Ig genes. However, its mechanism to initiate these genetic alterations is still unclear. AID can convert cytosine to uracil on either mRNA or DNA and is involved in DNA cleavage. Although these events are expected to take place in the nucleus, overexpressed AID was found predominantly in the cytoplasm. Here, we demonstrated that AID is a nucleocytoplasmic shuttling protein with a bipartite nuclear localization signal and a nuclear export signal in its N and C termini, respectively. In addition to previously identified genetic, structural, and biochemical similarities of AID with apolipoprotein B mRNA editing catalytic polypeptide 1, an RNA editing enzyme of ApoB100 mRNA, the present finding provides another aspect to their resemblance, suggesting that both may have homologous reaction mechanisms.

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