title: The prereplication complex recruits XEco2 to chromatin to promote cohesin acetylation in Xenopus egg extracts.
abstract: BACKGROUND
  Sister chromatids are held together by the ring-shaped cohesin complex, which is loaded onto chromosomes before DNA replication. Cohesion between sister chromosomes is established during DNA replication, and it requires acetylation of the Smc3 subunit of cohesin by evolutionally conserved cohesin acetyltransferases (CoATs). However, how CoATs are recruited to chromatin and how cohesin acetylation is regulated remain unclear.
  
  
  RESULTS
  We found that cohesin acetylation requires pre-RC-dependent chromatin loading of cohesin, but surprisingly, it is independent of DNA synthesis in Xenopus egg extracts. Immunodepletion experiments revealed that XEco2 is the CoAT responsible for Smc3 acetylation and sister chromatid cohesion. Recruitment of XEco2 onto chromatin was dependent on pre-RC assembly but was independent of cohesin loading and DNA synthesis. Two short N-terminal motifs, PBM-A and PBM-B, which are conserved among vertebrate Esco2/XEco2 homologs, were collectively essential for pre-RC-dependent chromatin association of XEco2, cohesin acetylation, and subsequent sister chromatid cohesion. The conserved PCNA-interacting protein box in XEco2 was largely dispensable for Smc3 acetylation but was partially required for cohesion. Interaction of acetylated cohesin with DNA was stabilized against salt-wash treatments after DNA replication.
  
  
  CONCLUSIONS
  Our results demonstrate that pre-RC formation regulates chromatin association of XEco2 in Xenopus egg extracts. We propose that this reaction is critical to acetylate cohesin, whose DNA binding is subsequently stabilized by DNA replication.
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Torahiko L
authors.initials: TL
authors.lastname: Higashi
authors.forename: Megumi
authors.initials: M
authors.lastname: Ikeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Takuro
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Masashige
authors.initials: M
authors.lastname: Bando
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Shirahige
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kubota
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Takisawa
authors.forename: Hisao
authors.initials: H
authors.lastname: Masukata
authors.forename: Tatsuro S
authors.initials: TS
authors.lastname: Takahashi
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002842:Chromatids / Q000502:physiology*; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004261:DNA Replication; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D010063:Ovum / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D014981:Xenopus; D029867:Xenopus Proteins / Q000378:metabolism*; D000097722:Cohesins
chemical_list: D000123:Acetyltransferases; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D018809:Proliferating Cell Nuclear Antigen; D017346:Protein Serine-Threonine Kinases; D029867:Xenopus Proteins; D000097722:Cohesins; C541512:SMC3 protein, Xenopus; C575500:Eco2 protein, Xenopus; C489405:CDC7 protein, Xenopus