Cdc7-Drf1 kinase links chromosome cohesion to the initiation of DNA replication in Xenopus egg extracts.
To establish functional cohesion between replicated sister chromatids, cohesin is recruited to chromatin before S phase. Cohesin is loaded onto chromosomes in the G1 phase by the Scc2-Scc4 complex, but little is known about how Scc2-Scc4 itself is recruited to chromatin. Using Xenopus egg extracts as a vertebrate model system, we showed previously that the chromatin association of Scc2 and cohesin is dependent on the prior establishment of prereplication complexes (pre-RCs) at origins of replication. Here, we report that Scc2-Scc4 exists in a stable complex with the Cdc7-Drf1 protein kinase (DDK), which is known to bind pre-RCs and activate them for DNA replication. Immunodepletion of DDK from Xenopus egg extracts impairs chromatin association of Scc2-Scc4, a defect that is reversed by wild-type, but not catalytically inactive DDK. A complex of Scc4 and the N terminus of Scc2 is sufficient for chromatin loading of Scc2-Scc4, but not for cohesin recruitment. These results show that DDK is required to tether Scc2-Scc4 to pre-RCs, and they underscore the intimate link between early steps in DNA replication and cohesion.
Takahashi
Tatsuro S
TS
Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA. tatsuro-takahashi@bio.sci.osaka-u.ac.jp
Basu
Abhijit
A
Bermudez
Vladimir
V
Hurwitz
Jerard
J
Walter
Johannes C
JC
D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002457:Cell Extracts; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins; D015151:Immunoblotting; D008938:Mitosis / Q000502:physiology; D009865:Oocytes / Q000166:cytology / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits; D012854:Sister Chromatid Exchange; D029867:Xenopus Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014982:Xenopus laevis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002457:Cell Extracts; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D017346:Protein Serine-Threonine Kinases; D029867:Xenopus Proteins; D000097722:Cohesins; C505573:DBF4B protein, Xenopus; C505572:Dbf4 protein, Xenopus; C515655:MAU2 protein, human; C492914:Scc2 protein, Xenopus; C489405:CDC7 protein, Xenopus