The molecular basis of selective DNA binding by the BRG1 AT-hook and bromodomain

Biochim Biophys Acta Gene Regul Mech. 2020 Aug;1863(8):194566. doi: 10.1016/j.bbagrm.2020.194566. Epub 2020 May 3.

Abstract

The ATP-dependent BAF chromatin remodeling complex plays a critical role in gene regulation by modulating chromatin architecture, and is frequently mutated in cancer. Indeed, subunits of the BAF complex are found to be mutated in >20% of human tumors. The mechanism by which BAF properly navigates chromatin is not fully understood, but is thought to involve a multivalent network of histone and DNA contacts. We previously identified a composite domain in the BRG1 ATPase subunit that is capable of associating with both histones and DNA in a multivalent manner. Mapping the DNA binding pocket revealed that it contains several cancer mutations. Here, we utilize SELEX-seq to investigate the DNA specificity of this composite domain and NMR spectroscopy and molecular modelling to determine the structural basis of DNA binding. Finally, we demonstrate that cancer mutations in this domain alter the mode of DNA association.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Base Pairing
  • Chromatin
  • Chromatin Assembly and Disassembly
  • DNA / metabolism*
  • DNA Helicases / chemistry
  • DNA Helicases / genetics
  • DNA Helicases / metabolism*
  • Gene Expression Regulation
  • Histones / metabolism
  • Humans
  • Molecular Dynamics Simulation
  • Mutation
  • Neoplasms / genetics
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Conformation
  • Protein Domains*
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • Chromatin
  • Histones
  • Nuclear Proteins
  • Transcription Factors
  • DNA
  • SMARCA4 protein, human
  • DNA Helicases