Alignment and quantification of ChIP-exo crosslinking patterns reveal the spatial organization of protein-DNA complexes

Nucleic Acids Res. 2020 Nov 18;48(20):11215-11226. doi: 10.1093/nar/gkaa618.

Abstract

The ChIP-exo assay precisely delineates protein-DNA crosslinking patterns by combining chromatin immunoprecipitation with 5' to 3' exonuclease digestion. Within a regulatory complex, the physical distance of a regulatory protein to DNA affects crosslinking efficiencies. Therefore, the spatial organization of a protein-DNA complex could potentially be inferred by analyzing how crosslinking signatures vary between its subunits. Here, we present a computational framework that aligns ChIP-exo crosslinking patterns from multiple proteins across a set of coordinately bound regulatory regions, and which detects and quantifies protein-DNA crosslinking events within the aligned profiles. By producing consistent measurements of protein-DNA crosslinking strengths across multiple proteins, our approach enables characterization of relative spatial organization within a regulatory complex. Applying our approach to collections of ChIP-exo data, we demonstrate that it can recover aspects of regulatory complex spatial organization at yeast ribosomal protein genes and yeast tRNA genes. We also demonstrate the ability to quantify changes in protein-DNA complex organization across conditions by applying our approach to analyze Drosophila Pol II transcriptional components. Our results suggest that principled analyses of ChIP-exo crosslinking patterns enable inference of spatial organization within protein-DNA complexes.

Publication types

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

MeSH terms

  • Algorithms
  • Animals
  • Binding Sites
  • Chromatin Immunoprecipitation / methods*
  • Computer Simulation
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / metabolism*
  • Databases, Genetic
  • Drosophila / chemistry
  • Drosophila / genetics
  • Drosophila / metabolism
  • Exonucleases / chemistry*
  • Promoter Regions, Genetic
  • Protein Binding
  • RNA Polymerase II / chemistry
  • RNA Polymerase II / genetics
  • RNA Polymerase II / metabolism
  • RNA Polymerase III / chemistry
  • RNA Polymerase III / genetics
  • RNA Polymerase III / metabolism
  • RNA, Transfer / chemistry
  • RNA, Transfer / genetics*
  • RNA, Transfer / metabolism
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / genetics*
  • Ribosomal Proteins / metabolism
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Sequence Alignment / methods*
  • Sequence Analysis, DNA / methods
  • Transcription Factor TFIIIB / chemistry
  • Transcription Factor TFIIIB / genetics
  • Transcription Factor TFIIIB / metabolism
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription Factors, TFIII / chemistry
  • Transcription Factors, TFIII / genetics
  • Transcription Factors, TFIII / metabolism
  • Transcription Initiation Site

Substances

  • DNA-Binding Proteins
  • Ribosomal Proteins
  • Saccharomyces cerevisiae Proteins
  • TFC1 protein, S cerevisiae
  • Transcription Factor TFIIIB
  • Transcription Factors
  • Transcription Factors, TFIII
  • transcription factor TFIIIC
  • RNA, Transfer
  • RNA Polymerase II
  • RNA Polymerase III
  • Exonucleases