Mcm10 and the MCM2-7 complex interact to initiate DNA synthesis and to release replication factors from origins.
MCM2-7, a complex of six subunits, is an essential component of the prereplication chromatin that is assembled at Saccharomyces cerevisiae replication origins during G(1) phase. It is also believed to be the processive helicase at growing forks. To elucidate the action of MCM2-7 during the transition from initiation to elongation replication, we have focused our studies on Mcm10, a replication initiation protein that physically interacts with members of the MCM2-7 complex. We show that Mcm10 is a chromatin-associated protein that mediates the association of the MCM2-7 complex with replication origins. Furthermore, diminished interaction between Mcm10 and Mcm7, a subunit of the MCM2-7 complex, by a mutation in either Mcm10 or Mcm7 inhibits replication initiation. Surprisingly, a double mutant containing both the mcm10-1 and mcm7-1 (cdc47-1) alleles restores interaction between Mcm10 and Mcm7 and corrects all of the defects exhibited by each of the single mutants, including the stalling of replication forks at replication origins typically seen in mcm10-1 cells. This mutual compensation of defects between two independently isolated mutations is allele specific. These results suggest that Mcm10, like Mcm7, is a critical component of the prereplication chromatin and that interaction between Mcm10 and Mcm7 is required for proper replication initiation and prompt release of origin-bound factors.
Homesley
L
L
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853-2703, USA.
Lei
M
M
Kawasaki
Y
Y
Sawyer
S
S
Christensen
T
T
Tye
B K
BK
D000483:Alleles; D000595:Amino Acid Sequence; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D003433:Crosses, Genetic; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D016193:G1 Phase; D064168:Minichromosome Maintenance Complex Component 7; D064110:Minichromosome Maintenance Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D010641:Phenotype; D010957:Plasmids; D018741:Replication Origin; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D020798:Two-Hybrid System Techniques
C102209:CDC45 protein, S cerevisiae; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C076365:MCM10 protein, S cerevisiae; C489613:MCM10 protein, human; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; C069199:MCM2 protein, S cerevisiae; C491088:MCM7 protein, S cerevisiae; D064168:Minichromosome Maintenance Complex Component 7; D064110:Minichromosome Maintenance Proteins