title: A role for USP7 in DNA replication.
abstract: The minichromosome maintenance (MCM) complex, which plays multiple important roles in DNA replication, is loaded onto chromatin following mitosis, remains on chromatin until the completion of DNA synthesis, and then is unloaded by a poorly defined mechanism that involves the MCM binding protein (MCM-BP). Here we show that MCM-BP directly interacts with the ubiquitin-specific protease USP7, that this interaction occurs predominantly on chromatin, and that MCM-BP can tether USP7 to MCM proteins. Detailed biochemical and structure analyses of the USP7-MCM-BP interaction showed that the (155)PSTS(158) MCM-BP sequence mediates critical interactions with the TRAF domain binding pocket of USP7. Analysis of the effects of USP7 knockout on DNA replication revealed that lack of USP7 results in slowed progression through late S phase without globally affecting the fork rate or origin usage. Lack of USP7 also resulted in increased levels of MCM proteins on chromatin, and investigation of the cause of this increase revealed a defect in the dissociation of MCM proteins from chromatin in mid- to late S phase. This role of USP7 mirrors the previously described role for MCM-BP in MCM complex unloading and suggests that USP7 works with MCM-BP to unload MCM complexes from chromatin at the end of S phase.
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto, Canada.
authors.forename: Madhav
authors.initials: M
authors.lastname: Jagannathan
authors.forename: Tin
authors.initials: T
authors.lastname: Nguyen
authors.forename: David
authors.initials: D
authors.lastname: Gallo
authors.forename: Niharika
authors.initials: N
authors.lastname: Luthra
authors.forename: Grant W
authors.initials: GW
authors.lastname: Brown
authors.forename: Vivian
authors.initials: V
authors.lastname: Saridakis
authors.forename: Lori
authors.initials: L
authors.lastname: Frappier
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004261:DNA Replication; D005434:Flow Cytometry; D016193:G1 Phase / Q000235:genetics; D045325:HCT116 Cells; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D064168:Minichromosome Maintenance Complex Component 7 / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D016196:S Phase / Q000235:genetics; D043222:Ubiquitin Thiolesterase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000076084:Ubiquitin-Specific Peptidase 7
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D002843:Chromatin; C489423:MCM5 protein, human; C519407:MCMBP protein, human; D009687:Nuclear Proteins; C464569:USP7 protein, human; D043222:Ubiquitin Thiolesterase; D000076084:Ubiquitin-Specific Peptidase 7; C101624:MCM7 protein, human; D064168:Minichromosome Maintenance Complex Component 7