title: Mcm10 associates with the loaded DNA helicase at replication origins and defines a novel step in its activation.
abstract: Mcm10 is essential for chromosome replication in eukaryotic cells and was previously thought to link the Mcm2-7 DNA helicase at replication forks to DNA polymerase alpha. Here, we show that yeast Mcm10 interacts preferentially with the fraction of the Mcm2-7 helicase that is loaded in an inactive form at origins of DNA replication, suggesting a role for Mcm10 during the initiation of chromosome replication, but Mcm10 is not a stable component of the replisome subsequently. Studies with budding yeast and human cells indicated that Mcm10 chaperones the catalytic subunit of polymerase alpha and preserves its stability. We used a novel degron allele to inactivate Mcm10 efficiently and this blocked the initiation of chromosome replication without causing degradation of DNA polymerase alpha. Strikingly, the other essential helicase subunits Cdc45 and GINS were still recruited to Mcm2-7 when cells entered S-phase without Mcm10, but origin unwinding was blocked. These findings indicate that Mcm10 is required for a novel step during activation of the Cdc45-MCM-GINS helicase at DNA replication origins.
authors.affiliation: Paterson Institute for Cancer Research, University of Manchester, Manchester, UK.
authors.forename: Frederick
authors.initials: F
authors.lastname: van Deursen
authors.forename: Sugopa
authors.initials: S
authors.lastname: Sengupta
authors.forename: Giacomo
authors.initials: G
authors.lastname: De Piccoli
authors.forename: Alberto
authors.initials: A
authors.lastname: Sanchez-Diaz
authors.forename: Karim
authors.initials: K
authors.lastname: Labib
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004265:DNA Helicases / Q000378:metabolism*; D004261:DNA Replication; D004271:DNA, Fungal / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D015003:Yeasts
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004271:DNA, Fungal; D005656:Fungal Proteins; D017493:Leukocyte Common Antigens; D004265:DNA Helicases