Intrinsic coupling of lagging-strand synthesis to chromatin assembly

Nature. 2012 Mar 14;483(7390):434-8. doi: 10.1038/nature10895.

Abstract

Fifty per cent of the genome is discontinuously replicated on the lagging strand as Okazaki fragments. Eukaryotic Okazaki fragments remain poorly characterized and, because nucleosomes are rapidly deposited on nascent DNA, Okazaki fragment processing and nucleosome assembly potentially affect one another. Here we show that ligation-competent Okazaki fragments in Saccharomyces cerevisiae are sized according to the nucleosome repeat. Using deep sequencing, we demonstrate that ligation junctions preferentially occur near nucleosome midpoints rather than in internucleosomal linker regions. Disrupting chromatin assembly or lagging-strand polymerase processivity affects both the size and the distribution of Okazaki fragments, suggesting a role for nascent chromatin, assembled immediately after the passage of the replication fork, in the termination of Okazaki fragment synthesis. Our studies represent the first high-resolution analysis--to our knowledge--of eukaryotic Okazaki fragments in vivo, and reveal the interconnection between lagging-strand synthesis and chromatin assembly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatin Assembly and Disassembly / physiology*
  • DNA / biosynthesis*
  • DNA / genetics
  • DNA / metabolism
  • DNA Ligase ATP
  • DNA Ligases / deficiency
  • DNA Ligases / metabolism
  • DNA Polymerase III / metabolism
  • DNA Replication*
  • DNA-Binding Proteins / metabolism
  • High-Throughput Nucleotide Sequencing
  • Nucleosomes / genetics
  • Nucleosomes / metabolism*
  • Protein Binding
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Transcription Factors / metabolism

Substances

  • DNA-Binding Proteins
  • Nucleosomes
  • Okazaki fragments
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • DNA
  • DNA Polymerase III
  • DNA Ligases
  • DNA Ligase ATP

Associated data

  • GEO/GSE33786