Quantitative classification of chromatin dynamics reveals regulators of intestinal stem cell differentiation

Abstract

Intestinal stem cell (ISC) plasticity is thought to be regulated by broadly-permissive chromatin shared between ISCs and their progeny. Here, we utilize a Sox9EGFP reporter to examine chromatin across ISC differentiation. We find that open chromatin regions (OCRs) can be defined as broadly-permissive or dynamic in a locus-specific manner, with dynamic OCRs found primarily in loci consistent with distal enhancers. By integrating gene expression with chromatin accessibility at transcription factor (TF) motifs in context of Sox9EGFP populations, we classify broadly-permissive and dynamic chromatin relative to TF usage. These analyses identify known and potential regulators of ISC differentiation via their association with dynamic changes in chromatin. We observe ISC expansion in Id3-null mice, consistent with computational predictions. Finally, we examine the relationship between gene expression and 5-hydroxymethylcytosine (5hmC) in Sox9EGFP populations, which reveals 5hmC enrichment in absorptive lineage specific genes. Our data demonstrate that intestinal chromatin dynamics can be quantitatively defined in a locus-specific manner, identify novel potential regulators of ISC differentiation, and provide a chromatin roadmap for further dissecting the role of cis regulation of cell fate in the intestine.