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

ABSTRACT: During B cell development, the precursor B cell receptor (pre-BCR) checkpoint is thought to increase immunoglobulin ? light chain (Ig?) 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(?) transcription. To investigate whether pre-BCR signaling modulates V(?) accessibility through enhancer-mediated Ig? locus topology, we performed chromosome conformation capture and sequencing analyses. These revealed that already in pro-B cells the ? enhancers robustly interact with the ?3.2 Mb V(?) 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 Ig? locus flanking sequences and increases interactions of the 3'? enhancer with V(?) genes. Remarkably, pre-BCR signaling does not significantly affect interactions between the intronic enhancer and V(?) genes, which are already robust in pro-B cells. Both enhancers interact most frequently with highly used V(?) genes, which are often marked by transcription factor E2a. We conclude that the ? enhancers interact with the V(?) 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(?) region, whereby the two enhancers play distinct roles.

SUBMITTER: Stadhouders R 

PROVIDER: S-EPMC3928034 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature