Document Detail


Expression of AID transgene is regulated in activated B cells but not in resting B cells and kidney.
MedLine Citation:
PMID:  18067961     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Activation-induced DNA cytidine deaminase (AID) is required for somatic hypermutation (SHM) and efficient class switch recombination (CSR) of immunoglobulin (Ig) genes. We created AID-transgenic mice that express AID ubiquitously under the control of a beta-actin promoter. When crossed with AID-/- mice, the AID-transgenic,AID-/- mice carried out SHM and CSR, showing that the AID transgenes were functional. However, the frequencies of SHM in V- and switch-regions, and CSR were reduced compared to those in a wild type AID background. Several criteria suggested that the inefficiency of SHM was due to reduced AID activity, rather than lack of recruiting error-prone DNA repair. High levels of AID mRNA were produced in resting B cells and kidney, cells that do not express AID in wild type mice. Compared with these cells, activated B cells expressed about an order of magnitude less AID mRNA suggesting that there may be a post-transcriptional mechanism that regulates AID mRNA levels in professional AID producers but not other cells. The AID protein expressed in resting B cells and kidney was phosphorylated at serine-38. Despite this modification, known to enhance AID activity, resting B cells did not undergo SHM. Apparently, the large amounts of AID in resting B cells are not targeted to Ig genes in vivo, in contrast to findings in vitro.
Authors:
Hong Ming Shen; Grazyna Bozek; Carl A Pinkert; Kevin McBride; Lili Wang; Amy Kenter; Ursula Storb
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2007-12-11
Journal Detail:
Title:  Molecular immunology     Volume:  45     ISSN:  0161-5890     ISO Abbreviation:  Mol. Immunol.     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2008-02-18     Completed Date:  2008-04-24     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  7905289     Medline TA:  Mol Immunol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1883-92     Citation Subset:  IM    
Affiliation:
Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
B-Lymphocytes / cytology*,  enzymology*
Cytidine Deaminase / genetics*
Flow Cytometry
Gene Expression Regulation, Enzymologic*
Immunoglobulin Class Switching / immunology
Kidney / enzymology*
Lymphocyte Activation / immunology*
Mice
Mice, Inbred C57BL
Mutation / genetics
Phosphorylation
Proliferating Cell Nuclear Antigen / metabolism
RNA, Messenger / genetics,  metabolism
Serine / metabolism
Somatic Hypermutation, Immunoglobulin / immunology
Transgenes*
Grant Support
ID/Acronym/Agency:
AI052400/AI/NIAID NIH HHS; AI053130/AI/NIAID NIH HHS; R01 AI047380-07/AI/NIAID NIH HHS; R01 AI052400-05A2/AI/NIAID NIH HHS; R01 AI053130-05/AI/NIAID NIH HHS
Chemical
Reg. No./Substance:
0/Proliferating Cell Nuclear Antigen; 0/RNA, Messenger; 56-45-1/Serine; EC 3.5.4.-/AICDA (activation-induced cytidine deaminase); EC 3.5.4.5/Cytidine Deaminase
Comments/Corrections

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