Pre-B cell receptor signaling induces immunoglobulin κ locus accessibility by functional redistribution of enhancer-mediated chromatin interactions

PLoS Biol. 2014 Feb 18;12(2):e1001791. doi: 10.1371/journal.pbio.1001791. eCollection 2014 Feb.

Abstract

During B cell development, the precursor B cell receptor (pre-BCR) checkpoint is thought to increase immunoglobulin κ light chain (Igκ) locus accessibility to the V(D)J recombinase. Accordingly, pre-B cells lacking the pre-BCR signaling molecules Btk or Slp65 showed reduced germline V(κ) transcription. To investigate whether pre-BCR signaling modulates V(κ) accessibility through enhancer-mediated Igκ locus topology, we performed chromosome conformation capture and sequencing analyses. These revealed that already in pro-B cells the κ enhancers robustly interact with the ∼3.2 Mb V(κ) region and its flanking sequences. Analyses in wild-type, Btk, and Slp65 single- and double-deficient pre-B cells demonstrated that pre-BCR signaling reduces interactions of both enhancers with Igκ locus flanking sequences and increases interactions of the 3'κ enhancer with V(κ) genes. Remarkably, pre-BCR signaling does not significantly affect interactions between the intronic enhancer and V(κ) genes, which are already robust in pro-B cells. Both enhancers interact most frequently with highly used V(κ) genes, which are often marked by transcription factor E2a. We conclude that the κ enhancers interact with the V(κ) region already in pro-B cells and that pre-BCR signaling induces accessibility through a functional redistribution of long-range chromatin interactions within the V(κ) region, whereby the two enhancers play distinct roles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Chromatin / genetics
  • Chromatin / metabolism*
  • Chromatin Assembly and Disassembly
  • Enhancer Elements, Genetic*
  • Epistasis, Genetic
  • Histones / metabolism
  • Immunoglobulin kappa-Chains / genetics*
  • Immunoglobulin kappa-Chains / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Precursor Cells, B-Lymphoid / metabolism*
  • Protein Processing, Post-Translational
  • Receptors, Antigen, B-Cell / genetics
  • Receptors, Antigen, B-Cell / metabolism
  • Signal Transduction
  • Transcriptome
  • V(D)J Recombination

Substances

  • Chromatin
  • Histones
  • Immunoglobulin kappa-Chains
  • Receptors, Antigen, B-Cell

Grants and funding

This work was partly supported by Fundação para a Ciência e a Tecnologia (to CRA), the International Association for Cancer Research (AICR 10-0562, to RWH), EpiGenSys/ERASysBio +/FP7 (NL: NWO, UK: BSRC, D: BMBF, to PK), the Center of Biomedical Genetics and the EU 6th Framework Programme EuTRACC Consortium (Project LSHG-CT-2007-037455; FG, ES, and RS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.