Recruitment of Xenopus Scc2 and cohesin to chromatin requires the pre-replication complex

Nat Cell Biol. 2004 Oct;6(10):991-6. doi: 10.1038/ncb1177. Epub 2004 Sep 26.

Abstract

Cohesin is a multi-subunit, ring-shaped protein complex that holds sister chromatids together from the time of their synthesis in S phase until they are segregated in anaphase. In yeast, the loading of cohesin onto chromosomes requires the Scc2 protein. In vertebrates, cohesins first bind to chromosomes as cells exit mitosis, but the mechanism is unknown. Concurrent with cohesin binding, pre-replication complexes (pre-RCs) are assembled at origins of DNA replication through the sequential loading of the initiation factors ORC, Cdc6, Cdt1 and MCM2-7 (the 'licensing' reaction). In S phase, the protein kinase Cdk2 activates pre-RCs, causing origin unwinding and DNA replication. Here, we use Xenopus egg extracts to show that the recruitment of cohesins to chromosomes requires fully licensed chromatin and is dependent on ORC, Cdc6, Cdt1 and MCM2-7, but is independent of Cdk2. We further show that Xenopus Scc2 is required for cohesin loading and that binding of XScc2 to chromatin is MCM2-7 dependent. Our results define a novel pre-RC-dependent pathway for cohesin recruitment to chromosomes in a vertebrate model system.

Publication types

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

MeSH terms

  • Animals
  • Cell Cycle Proteins / metabolism
  • Cell Extracts
  • Chromatin / metabolism*
  • Chromosomal Proteins, Non-Histone / chemistry*
  • Chromosomal Proteins, Non-Histone / isolation & purification
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Cohesins
  • DNA Replication
  • Electrophoresis, Gel, Two-Dimensional
  • Escherichia coli / genetics
  • Fungal Proteins
  • Male
  • Mass Spectrometry
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism*
  • Oocytes / chemistry
  • Replication Origin*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Spermatozoa / chemistry
  • Xenopus
  • Xenopus Proteins / chemistry*
  • Xenopus Proteins / isolation & purification
  • Xenopus Proteins / metabolism*

Substances

  • CDC6 protein, S cerevisiae
  • Cell Cycle Proteins
  • Cell Extracts
  • Chromatin
  • Chromosomal Proteins, Non-Histone
  • Fungal Proteins
  • Nuclear Proteins
  • SCC2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Scc2 protein, Xenopus
  • Xenopus Proteins

Associated data

  • GENBANK/AY731711