title: Transcription factor Pax5 (BSAP) transactivates the RAG-mediated V(H)-to-DJ(H) rearrangement of immunoglobulin genes.
abstract: Immunoglobulin rearrangement from variable heavy chain (V(H)) to diversity (D)-joining heavy chain (J(H)), which occurs exclusively in B lineage cells, is impaired in mice deficient for the B lineage-specific transcription factor Pax5. Conversely, ectopic Pax5 expression in thymocytes promotes the rearrangement of D(H)-proximal V(H)7183 genes. In exploring the mechanism for Pax5 regulation of V(H)-to-DJ(H) recombination, we have identified multiple Pax5 binding sites in the coding regions of human and mouse V(H) gene segments. Pax5 bound to those sites in vitro and occupied V(H) genes in early human and mouse B lineage cells. Moreover, Pax5 interacted with the recombination-activating gene 1 (RAG1)-RAG2 complex to enhance RAG-mediated V(H) recombination signal sequence cleavage and recombination of a V(H) gene substrate. These findings indicate a direct activating function for Pax5 in RAG-mediated immunoglobulin V(H)-to-DJ(H) recombination.
authors: Division of Developmental and Clinical Immunology, University of Alabama at Birmingham, 35294, USA. zhixin.zhang@ccc.uab.edu
authors: Zhixin
authors: Z
authors: Zhang
authors: Celia R
authors: CR
authors: Espinoza
authors: Zhihong
authors: Z
authors: Yu
authors: Robert
authors: R
authors: Stephan
authors: Ti
authors: T
authors: He
authors: G Stuart
authors: GS
authors: Williams
authors: Peter D
authors: PD
authors: Burrows
authors: James
authors: J
authors: Hagman
authors: Ann J
authors: AJ
authors: Feeney
authors: Max D
authors: MD
authors: Cooper