title: Accessibility control and machinery of immunoglobulin class switch recombination.
abstract: Immunoglobulin (Ig) class switching is a process by which B lymphocytes shift from production of IgM to other Ig classes and subclasses via Ig class switch recombination (CSR). Multiple cellular and molecular processes are involved in CSR. Induction of a given IgH germline transcription initiates CSR processes. Ig germline transcription is selectively activated and induced by specific cytokine(s) via cytokine-specific signal pathways, synergized by CD40 signaling, and optimized by the 3' Ig alpha enhancers through locus control region function. Following Ig germline transcription, the switch-region DNA undergoes conformational changes so that it can serve as an appropriate substrate for nicking and cleavage by switch recombination machinery. Finally, the double-strand breaks in donor and acceptor switch DNAs are processed, repaired, and ligated through a general nonhomologous end join pathway. CSR generates a new transcriptional unit for production of a class-switched Ig isotype.
authors.affiliation: The Hart and Louse Lyon Laboratory, Division of Clinical Immunology/Allergy, Department of Medicine, University of California Los Angeles, School of Medicine, 90095-1680, USA. kzhang@mednet.ucla.edu
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
mesh_terms: D005786:Gene Expression Regulation; D006801:Humans; D017578:Immunoglobulin Class Switching / Q000235:genetics*; D007074:Immunoglobulin G / Q000235:genetics; D007134:Immunoglobulin Switch Region / Q000235:genetics; D011995:Recombination, Genetic; D014158:Transcription, Genetic
chemical_list: D007074:Immunoglobulin G