title: Orchestration of B lymphoid cells and their inner myeloid by Bach.
abstract: The transcription repressor Bach2 is required for class switch recombination and somatic hypermutation of antibody genes in B cells, and proper development of effector and regulatory T cells. In addition, Bach2 and its related factor Bach1 promote B cell commitment of progenitor cells by repressing myeloid-related genes. Bach2 and the myeloid regulators C/EBPβ and C/EBPα mutually repress their expression, forming a gene regulatory network (GRN) that dictates the process of lineage commitment. Bach2 forms another GRN with the plasma cell regulator Blimp-1, in which Bach2 and Blimp-1 mutually repress their expression. Since Bach2 expression is reduced in plasma cells, the repression of myeloid-related genes in B cells may be dissolved upon terminal differentiation of B cells to plasma cells. The Bach2 GRNs support the myeloid-based model of hematopoiesis. Myeloid-like characteristics suppressed or manifested in B cells by modifying differentiation trajectories of B and myeloid cells may be termed as 'inner myeloid' after the concept of 'inner fish'.
authors.affiliation: Department of Biochemistry and Center for Regulatory Epigenome and Diseases, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan. Electronic address: igarashi@med.tohoku.ac.jp.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Igarashi
authors.affiliation: Department of Experimental Immunology, Institute of Development, Aging and Cancer, Tohoku University, Seiryo-machi 4-1, Sendai 980-8575, Japan.
authors.forename: Ari
authors.initials: A
authors.lastname: Itoh-Nakadai
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D050976:Basic-Leucine Zipper Transcription Factors / Q000502:physiology*; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D002454:Cell Differentiation; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D017578:Immunoglobulin Class Switching / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology
chemical_list: C491123:BACH2 protein, human; D050976:Basic-Leucine Zipper Transcription Factors; D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins; C515848:CEBPA protein, human; C545012:CEBPB protein, human