Interaction between antibody-diversification enzyme AID and spliceosome-associated factor CTNNBL1.
Activation-induced deaminase (AID) deaminates deoxycytidine residues in immunoglobulin genes, triggering antibody diversification. Here, by use of two-hybrid and coimmunoprecipitation assays, we identify CTNNBL1 (also known as NAP) as an AID-specific interactor. Mutants of AID that interfere with CTNNBL1 interaction yield severely diminished hypermutation and class switching. Targeted inactivation of CTNNBL1 in DT40 B cells also considerably diminishes IgV diversification. CTNNBL1 is a widely expressed nuclear protein that associates with the Prp19 complex of the spliceosome, interacting with its CDC5L component. The results, therefore, identify residues in AID involved in its in vivo targeting and suggest they might act through interaction with CTNNBL1, giving possible insight into the linkage between AID recruitment and target-gene transcription.
Conticello
Silvestro G
SG
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK. Electronic address: silvo.conticello@ittumori.it.
Ganesh
Karuna
K
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
Xue
Kanmin
K
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
Lu
Mason
M
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
Rada
Cristina
C
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
Neuberger
Michael S
MS
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK. Electronic address: msn@mrc-lmb.cam.ac.uk.
D000818:Animals; D000916:Antibody Diversity; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002645:Chickens; D003564:Cytidine Deaminase / Q000378:metabolism*; D006801:Humans; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D017381:Spliceosomes / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
D051017:Apoptosis Regulatory Proteins; C508357:CDC5L protein, human; C479429:CTNNBL1 protein, human; D018797:Cell Cycle Proteins; D050505:Mutant Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D003564:Cytidine Deaminase