Human INT6 interacts with MCM7 and regulates its stability during S phase of the cell cycle.
The mouse int6 gene is a frequent integration site of the mouse mammary tumor virus and INT6 silencing by RNA interference in HeLa cells causes an increased number of cells in the G2/M phases of the cell cycle, along with mitotic defects. In this report, we investigated the functional significance of the interaction between INT6 and MCM7, which was observed in a two-hybrid screen performed with INT6 as bait. It was found that proteasome inhibition strengthens interaction between both proteins and that INT6 stabilizes MCM7. Removal of MCM7 from chromatin as replication proceeds was accelerated in INT6-silenced cells and reduced amounts of protein were transiently observed, followed by a correction resulting from stimulation of mcm7 gene expression. Synchronized cells depleted for either INT6 or MCM7 display a reduction in thymidine incorporation and a reinforced association of RPA and claspin with chromatin. These data show that INT6 stabilizes chromatin-bound MCM7 and that alteration of this effect is associated with replication deficiency.
Buchsbaum
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S
Laboratoire de Biologie Moléculaire de la Cellule, UMR5161 CNRS/ENS de Lyon, IFR 128 Biosciences Lyon Gerland, Lyon cedex 07, Rhone, France.
Morris
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C
Bochard
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Jalinot
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P
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D039621:Eukaryotic Initiation Factor-3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015894:Genome, Human; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D064168:Minichromosome Maintenance Complex Component 7; D009687:Nuclear Proteins / Q000378:metabolism*; D025821:Polyubiquitin / Q000378:metabolism; D061988:Proteasome Inhibitors; D016196:S Phase; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; C488158:CLSPN protein, human; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D039621:Eukaryotic Initiation Factor-3; D009687:Nuclear Proteins; D061988:Proteasome Inhibitors; D025821:Polyubiquitin; C101624:MCM7 protein, human; D064168:Minichromosome Maintenance Complex Component 7