title: E2A and CBP/p300 act in synergy to promote chromatin accessibility of the immunoglobulin κ locus.
abstract: V(D)J recombination of Ig and TCR genes is strictly regulated in a lineage- and stage-specific manner by the accessibility of target gene chromatin to the recombinases RAG1 and RAG2. It has been shown that enforced expression of the basic helix-loop-helix protein, E2A, together with RAG1/2 in a nonlymphoid cell line BOSC23 can induce V(D)J recombination in endogenous Igκ and TCR loci by increasing chromatin accessibility of target gene segments. In this study, we demonstrate that ectopically expressed E2A proteins in BOSC23 cells have the ability to bind directly to the promoter and recombination signal sequence of Vκ genes and to recruit histone acetyltransferase CBP/p300. Overexpression of CBP/p300 in conjunction with E2A results in enhancement of E2A-induced histone acetylation, germline transcription, and Igκ rearrangement. Conversely, knockdown of endogenous CBP/p300 expression by small interfering RNA leads to a decrease in histone acetylation, germline transcription and Igκ rearrangement. Furthermore, analyses using a mouse pre-B cell line revealed that endogenous E2A proteins also bind to a distinct set of Vκ genes and regulatory regions in the mouse Igκ locus and act to increase histone acetylation by recruiting p300, confirming the similar findings observed with BOSC23 cells. These observations indicate that E2A plays critical roles in inducing Igκ rearrangement by directly binding to and increasing chromatin accessibility at target gene segments.
authors.affiliation: Horizontal Medical Research Organization, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Kousho
authors.initials: K
authors.lastname: Wakae
authors.forename: Yuki
authors.initials: Y
authors.lastname: Anzai
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Murai
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Tamaki
authors.forename: Masaki
authors.initials: M
authors.lastname: Miyazaki
authors.forename: Kazuko
authors.initials: K
authors.lastname: Miyazaki
authors.forename: William J
authors.initials: WJ
authors.lastname: Romanow
authors.forename: Tomokatsu
authors.initials: T
authors.lastname: Ikawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kitamura
authors.forename: Itaru
authors.initials: I
authors.lastname: Yanagihara
authors.forename: Nagahiro
authors.initials: N
authors.lastname: Minato
authors.forename: Cornelis
authors.initials: C
authors.lastname: Murre
authors.forename: Yasutoshi
authors.initials: Y
authors.lastname: Agata
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D004357:Drug Synergism; D004742:Enhancer Elements, Genetic / Q000235:genetics / Q000276:immunology; D005854:Germ Cells / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D060152:V(D)J Recombination / Q000235:genetics; D050880:p300-CBP Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D002843:Chromatin; D006655:Histone Deacetylases; D007145:Immunoglobulin kappa-Chains; D050880:p300-CBP Transcription Factors; C407909:TCF3 protein, human