title: Regulation of Tcrb recombination ordering by c-Fos-dependent RAG deposition.
abstract: Antigen receptor variable-(diversity)-joining (V(D)J) recombination at the locus encoding the T cell antigen receptor-beta (Tcrb) is ordered, with D(beta)-to-J(beta) assembly preceding V(beta)-to-DJ(beta) joining. The molecular mechanism underlying this 'preferred' order of rearrangement remains unclear. Here we show that the D(beta) 23-base pair recombination signal sequence (D(beta) 23-RSS) contains a specific AP-1 transcription factor-binding site bound by AP-1 and its component c-Fos expressed at a specific stage. Cell-based recombination assays suggested that c-Fos interacted directly with the RAG recombinase and enhanced its deposition to D(beta) 23-RSSs, thus conferring the priority of DJ(beta) recombination. Loss of c-Fos decreased Tcrb recombination efficiency and disrupted recombination ordering in vivo. Our results show an unexpected function for c-Fos as a direct regulator of Tcrb recombination, rather than its usual function as a transcription regulator, and provide new insight into the mechanisms of recombination ordering.
authors.affiliation: Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Wang
authors.forename: Gang
authors.initials: G
authors.lastname: Xiao
authors.forename: Yafeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wen
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.forename: Seiji
authors.initials: S
authors.lastname: Okada
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Liu
mesh_terms: D000818:Animals; D001483:Base Sequence; D024202:Electrophoretic Mobility Shift Assay; D005434:Flow Cytometry; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor / Q000235:genetics*; D019674:Genes, T-Cell Receptor beta; D016762:Genes, fos / Q000502:physiology*; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D051379:Mice; D008969:Molecular Sequence Data; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics*; D045567:VDJ Recombinases / Q000378:metabolism*
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D018808:Transcription Factor AP-1; D045567:VDJ Recombinases