View the Current Issue

Article

  • The EMBO Journal (1998) 17, 5734 - 5743
  • doi:10.1093/emboj/17.19.5734

Identification of Bach2 as a B-cell-specific partner for small Maf proteins that negatively regulate the immunoglobulin heavy chain gene 3' enhancer

Akihiko Muto1,2, Hideto Hoshino1,2, Linda Madisen3, Nobuaki Yanai4, Masuo Obinata4, Hajime Karasuyama5, Norio Hayashi1, Hiromitsu Nakauchi2, Masayuki Yamamoto2, Mark Groudine3 and Kazuhiko Igarashi1

  1. Department of Biochemistry, Tohoku University School of Medicine, Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
  2. Institute of Basic Medical Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tenno-dai 1-1-1, Tsukuba 305, Japan
  3. Fred Hutchinson Cancer Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA
  4. Department of Cell Biology, Institute of Development, Aging and Cancer, Tohoku University, Seiryo-machi, Sendai 980-8575, Japan
  5. Department of Immunology, The Tokyo Metropolitan Institute of Medical Science, Honkomagome 3-18-22, Bunkyo-ku, Tokyo 113, Japan

Correspondence to:

Kazuhiko Igarashi, E-mail: igarak@mail.cc.tohoku.ac.jp

Received 31 March 1998; Accepted 3 August 1998; Revised 29 July 1998

Maf family transcription factors are important regulators in various differentiation systems. Putative Maf recognition elements (MAREs) are found in the 3' enhancer region of the immunoglobulin heavy chain (IgH) gene. These elements are bound in B-cell extracts by a heterodimeric protein complex containing both Bach2 and a small Maf protein. Analysis of normal hematopoietic cells revealed that Bach2 is specifically expressed in B cells. Bach2 is abundantly expressed in the early stages of B-cell differentiation and turned off in terminally differentiated cells. Bach2 acts together with MafK as a negative effector of the IgH 3' enhancer and binds to the co-repressor SMRT (silencing mediator of retinoid and thyroid receptor). Hence the Bach2–small-Maf heterodimer may represent the first example of a B-cell lineage, and of a developmental stage-restricted negative effector of the MARE in the IgH 3' enhancer region.

  • Keywords:

    • B cell,
    • immunoglobulin,
    • Maf,
    • transcription factor