Reciprocal regulation of cardiac chromatin by the chromatin structural proteins HMGB and CTCF

ABSTRACT: Transcriptome remodeling in heart disease occurs through the coordinated actions of transcription factors, histone modifications and other chromatin features at pathology-associated genes. It remains unknown the extent to which genome-wide chromatin reorganization also contributes to the pathologic gene expression. We examined the roles of two chromatin structural proteins, CTCF (CCCTC-binding factor) and HMGB2 (high mobility group protein B2), in regulating pathologic transcription and chromatin remodeling. Our data demonstrate a reciprocal relationship between HMGB2 and CTCF in controlling aspects of chromatin structure and gene expression. Both proteins regulate each other’s expression as well as transcription in cardiac myocytes: however, only HMGB2 does so in a manner that involves global reprogramming of chromatin accessibility. We demonstrate that the actions of HMGB2 on local chromatin accessibility are conserved across genomic loci, whereas the effects on transcription are loci-dependent and emerge in concert with histone modification and other chromatin features. Lastly, while both proteins share gene targets, HMGB2 and CTCF neither bind these genes simultaneously nor do they physically co-localize in myocyte nuclei. Our study uncovers a previously unknown relationship between these two ubiquitous chromatin proteins and provides a mechanistic explanation for how HMGB2 regulates gene expression and cellular phenotype. Furthermore, we demonstrate direct evidence for hierarchical remodeling of chromatin on a genome-wide scale in the setting of cardiac disease. Examination of a chromatin structural protein, HMGB2 in basal and agonist-treated cells.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Tom Vondriska 

PROVIDER: E-GEOD-80453 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress