title: Identification of a specific domain required for dimerization of activation-induced cytidine deaminase.
abstract: Activation-induced cytidine deaminase (AID) is essential to all three genetic alterations required for generation of antigen-specific immunoglobulin: class switch recombination, somatic hypermutation, and gene conversion. Here we demonstrate that AID molecules form a homodimer autonomously in the absence of RNA, DNA, other cofactors, or post-translational modifications. Studies on serial deletion mutants revealed the minimum region between Thr27 and His56 responsible for dimerization. Analyses of point mutations within this region revealed that the residues between Gly47 and Gly54 are most important for the dimer formation. Functional analyses of these mutations indicate that all mutations impairing the dimer formation are inefficient for class switching, suggesting that dimer formation is required for class switching activity. Dimer formation and its requirement for the function of AID are features that AID shares with APOBEC-1, an RNA editing enzyme of apolipoprotein B100 mRNA.
authors: Department of Immunology and Genomic Medicine, Graduate School of Medicine, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
authors: Jishu
authors: J
authors: Wang
authors: Reiko
authors: R
authors: Shinkura
authors: Masamichi
authors: M
authors: Muramatsu
authors: Hitoshi
authors: H
authors: Nagaoka
authors: Kazuo
authors: K
authors: Kinoshita
authors: Tasuku
authors: T
authors: Honjo