RRC ID 32579
Author Doi T, Kinoshita K, Ikegawa M, Muramatsu M, Honjo T.
Title De novo protein synthesis is required for the activation-induced cytidine deaminase function in class-switch recombination.
Journal Proc Natl Acad Sci U S A
Abstract Activation-induced cytidine deaminase (AID) is required for class-switch recombination (CSR), somatic hypermutation, and gene conversion of Ig genes. Although AID has sequence similarity to an RNA-editing enzyme Apobec-1, how AID functions in CSR and somatic hypermutation is unknown. Because involvement of RNA-editing but not DNA-editing in CSR requires de novo protein synthesis after AID expression, we examined whether protein synthesis inhibitors could block CSR in the presence of the AID activity. For this purpose we constructed AID fused with the hormone-binding domain of the estrogen receptor (AID-ER), which was introduced into AID-deficient spleen B cells. When such transfectants were treated with an estrogen analogue, 4-hydroxytamoxifen (OHT), CSR was induced within 1 h. Cycloheximide or puromycin drastically suppressed OHT-induced CSR in AID-ER expressing AID-/- B cells when added 1 h before OHT but not after OHT, suggesting that de novo protein synthesis is required for an event downstream to AID expression in CSR. The results lend the weight to RNA-editing hypothesis for the function of AID.
Volume 100(5)
Pages 2634-8
Published 2003-3-4
DOI 10.1073/pnas.0437710100
PII 0437710100
PMID 12591955
PMC PMC151392
MeSH Animals Blotting, Southern Blotting, Western Cycloheximide / pharmacology Cytidine Deaminase / metabolism* DNA / metabolism Dose-Response Relationship, Drug Enzyme Activation Estrogen Antagonists / pharmacology Flow Cytometry Genetic Vectors Green Fluorescent Proteins Immunoglobulin Class Switching Luminescent Proteins / metabolism Mice Mice, Inbred C57BL Mice, Inbred CBA Polymerase Chain Reaction Protein Structure, Tertiary Protein Synthesis Inhibitors / pharmacology Puromycin / pharmacology RNA / metabolism Receptors, Estrogen / metabolism Recombination, Genetic* Retroviridae / genetics Reverse Transcriptase Polymerase Chain Reaction Spleen / cytology Subcellular Fractions Tamoxifen / analogs & derivatives* Tamoxifen / pharmacology Time Factors
IF 9.412
Times Cited 85
DNA material pmAID-ER-FBG (RDB07086)