title: Cdt1 associates dynamically with chromatin throughout G1 and recruits Geminin onto chromatin.
abstract: To maintain genome integrity, eukaryotic cells initiate DNA replication once per cell cycle after assembling prereplicative complexes (preRCs) on chromatin at the end of mitosis and during G1. In S phase, preRCs are disassembled, precluding initiation of another round of replication. Cdt1 is a key member of the preRC and its correct regulation via proteolysis and by its inhibitor Geminin is essential to prevent premature re-replication. Using quantitative fluorescence microscopy, we study the interactions of Cdt1 with chromatin and Geminin in living cells. We find that Cdt1 exhibits dynamic interactions with chromatin throughout G1 phase and that the protein domains responsible for chromatin and Geminin interactions are separable. Contrary to existing in vitro data, we show that Cdt1 simultaneously binds Geminin and chromatin in vivo, thereby recruiting Geminin onto chromatin. We propose that dynamic Cdt1-chromatin associations and the recruitment of Geminin to chromatin provide spatio-temporal control of the licensing process.
authors.affiliation: Laboratory of General Biology, School of Medicine, University of Patras, Patras, Greece.
authors.forename: Georgia
authors.initials: G
authors.lastname: Xouri
authors.forename: Anthony
authors.initials: A
authors.lastname: Squire
authors.forename: Maria
authors.initials: M
authors.lastname: Dimaki
authors.forename: Bart
authors.initials: B
authors.lastname: Geverts
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Verveer
authors.forename: Stavros
authors.initials: S
authors.lastname: Taraviras
authors.forename: Hideo
authors.initials: H
authors.lastname: Nishitani
authors.forename: Adriaan B
authors.initials: AB
authors.lastname: Houtsmuller
authors.forename: Philippe I H
authors.initials: PI
authors.lastname: Bastiaens
authors.forename: Zoi
authors.initials: Z
authors.lastname: Lygerou
mesh_terms: D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism*; D036681:Fluorescence Recovery After Photobleaching / Q000379:methods; D016193:G1 Phase; D064248:Geminin; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D009010:Monte Carlo Method; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D002843:Chromatin; C577995:GMNN protein, human; D064248:Geminin; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins