Multiple lineage-specific epigenetic landscapes at the antigen receptor loci

TL;DR

This study compares epigenetic features of antigen receptor genes in different cell types, revealing distinct patterns in embryonic stem cells and immune cells.

Contribution

The study identifies lineage-specific epigenetic landscapes at antigen receptor loci in ES cells and lymphocytes.

Findings

AgR loci in ES cells show active histone modifications and transcription markers distinct from those in B and T cells.

Active histone modifications in ES cells co-localize with binding sites for Oct4, Sox2, and Nanog.

CTCF binding patterns overlap across ES cells, pro-B cells, and neurons despite other differences.

Abstract

Antigen receptors (AgRs) expressed on B and T cells provide the adaptive immune system with ability to detect numerous foreign antigens. Epigenetic features of B cell receptor (BCR) and T cell receptor (TCR) genes were previously studied in lymphocytes, but little is known about their epigenetic features in other cells. Here, we explored histone modifications and transcription markers at the BCR and TCR loci in lymphocytes (pro-B, DP T cells, and mature CD4+ T cells), compared to embryonic stem (ES) cells and neurons. In B cells, the BCR loci exhibited active histone modifications and transcriptional markers indicative of active loci. Similar results were observed at the TCR loci in T cells. All loci were largely inactive in neurons. Surprisingly, in ES cells all AgR loci displayed a high degree of active histone modifications and markers of active transcription. Locations of these active histone modifications in ES cells were largely distinct from those in pro-B cells, and co-localized at numerous binding locations for transcription factors Oct4, Sox2, and Nanog. ES and pro-B cells also showed distinct binding patterns for the ubiquitous transcription factor YY1 and chromatin remodeler Brg1. On the contrary, there were many overlapping CCCTC-binding factor (CTCF) binding patterns when comparing ES cells, pro-B cells, and neurons. Our study identifies epigenetic features in ES cells and lymphocytes that may be related to ES cell pluripotency and lymphocyte tissue-specific activation at the AgR loci.

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