title: Colocalization of human Rad17 and PCNA in late S phase of the cell cycle upon replication block.
abstract: In response to replication block or DNA damage in S phase the DNA replication and DNA damage checkpoints are activated. The current model in human predicts, that a Rad17/Replication factor C (RF-C) complex might serve as a recruitment complex for the Rad9/Hus1/Rad1 complex to sites of replication block or DNA damage. In this study we have investigated the fate of the Rad17/RF-C complex after treatment of synchronized Hela cells with the replication inhibitor hydroxyurea. In hydroxyurea treated cells the RF-C p37 subunit became more resistant to extraction. Moreover, co-immunoprecipitation studies with extracts of hydroxyurea treated cells showed an interaction of RF-C p37 with Rad17 and of PCNA with Rad9 and RF-C p37. An enhanced colocalization of Rad17 and PCNA in late S phase after hydroxyurea treatment was observed. Our data suggested, that upon replication block a Rad17/RF-C complex is recruited to sites of DNA lesions in late S phase, binds the Rad9/Hus1/Rad1 complex and enables it to interact with PCNA. An interaction of Rad17/RF-C with PCNA appears to be mediated by the small RF-C p37 subunit, suggesting that PCNA might provide communication between replication checkpoint control and DNA replication and repair.
authors.affiliation: Institute of Veterinary Biochemistry and Molecular Biology, University Zürich-Irchel, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Dahm
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hübscher
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D018809:Proliferating Cell Nuclear Antigen / Q000187:drug effects / Q000378:metabolism*; D015363:Quinolones / Q000494:pharmacology; D051818:Replication Protein C; D016196:S Phase / Q000187:drug effects / Q000502:physiology
chemical_list: C120195:4-nitroquinolone-1-oxide; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D018809:Proliferating Cell Nuclear Antigen; D015363:Quinolones; C497563:RFC4 protein, human; C113575:Rad17 protein, human; D015112:4-Nitroquinoline-1-oxide; D051818:Replication Protein C; D006918:Hydroxyurea