RBPJ binds to consensus and methylated cis elements within phased nucleosomes and controls gene expression in human aortic smooth muscle cells in cooperation with SRF

Nucleic Acids Res. 2018 Sep 19;46(16):8232-8244. doi: 10.1093/nar/gky562.

Abstract

Given our previous demonstration that RBPJ binds a methylated repressor element and regulates smooth muscle cell (SMC)-specific gene expression, we used genome-wide approaches to identify RBPJ binding regions in human aortic SMC and to assess RBPJ's effects on chromatin structure and gene expression. RBPJ bound to consensus cis elements, but also to TCmGGGA sequences within Alu repeats that were less transcriptionally active as assessed by DNAse hypersensitivity, H3K9 acetylation, and Notch3 and RNA Pol II binding. Interestingly, RBPJ binding was frequently detected at the borders of open chromatin, and a large fraction of genes induced or repressed by RBPJ depletion were associated with this cluster of RBPJ binding sites. RBPJ binding dramatically co-localized with serum response factor (SRF) and RNA seq experiments in RBPJ- and SRF-depleted SMC demonstrated that these factors interact functionally to regulate the contraction and inflammatory gene programs that help define SMC phenotype. Finally, we showed that RBPJ bound preferentially to phased nucleosomes independent of active chromatin marks and to cis elements positioned at the beginning and middle of the nucleosome dyad. These novel findings add important insight into RBPJ's role in chromatin structure and gene expression in SMC.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aorta / cytology
  • Base Sequence
  • Binding Sites / genetics
  • Cell Differentiation / genetics
  • Cell Line
  • DNA Methylation
  • Enhancer Elements, Genetic / genetics*
  • Gene Expression Regulation*
  • Humans
  • Immunoglobulin J Recombination Signal Sequence-Binding Protein / genetics*
  • Immunoglobulin J Recombination Signal Sequence-Binding Protein / metabolism
  • Myocytes, Smooth Muscle / metabolism*
  • Nucleosomes / genetics*
  • Nucleosomes / metabolism
  • Protein Binding
  • Serum Response Factor / genetics*
  • Serum Response Factor / metabolism

Substances

  • Immunoglobulin J Recombination Signal Sequence-Binding Protein
  • Nucleosomes
  • RBPJ protein, human
  • SRF protein, human
  • Serum Response Factor