Interactions between Mcm10p and other replication factors are required for proper initiation and elongation of chromosomal DNA replication in Saccharomyces cerevisiae.
BACKGROUND
MCM10 is essential for the initiation of chromosomal DNA replication in Saccharomyces cerevisiae. Previous work showed that Mcm10p interacts with the Mcm2-7 protein complex that may be functioning as the replication-licensing factor. In addition, Mcm10p is required during origin activation and disassembly of the prereplicative complex, which allows smooth passage of replication forks.


RESULTS
We show that an mcm10 mutation causes a slow progression of DNA synthesis and a loss of chromosome integrity during the S phase and prevents entry into mitosis, despite apparent completion of chromosomal DNA replication at nonpermissive temperatures. Furthermore, Mcm10p interacts genetically with the origin recognition complex (ORC) and various replication elongation factors, including a subunit of DNA polymerases epsilon and delta. Mcm10p is an abundant protein (approximately 4 x 10(4) copies per haploid cell) that is almost exclusively localized in the chromatin and/or nuclear matrix fractions during all phases of the cell cycle. When it is visualized by the chromosome-spreading method followed by immunostaining, Mcm10p forms punctate foci on chromatin throughout the cell cycle and these foci mostly overlap with those of Orc1p, a component of ORC.


CONCLUSIONS
These results suggest that Mcm10p, like the Mcm2-7 proteins, is a critical component of the prereplication chromatin and acts together with ORC during the initiation of chromosomal DNA replication; in addition, Mcm10p plays an important role during the elongation of DNA replication.
Kawasaki
Y
Y
Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Hiraga
S
S
Sugino
A
A
D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone; D015825:Chromosomes, Fungal / Q000235:genetics*; D003432:Cross-Linking Reagents / Q000737:chemistry; D004261:DNA Replication / Q000235:genetics*; D004271:DNA, Fungal / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D064110:Minichromosome Maintenance Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D051738:Origin Recognition Complex; D010441:Peptide Chain Elongation, Translational / Q000235:genetics; D010442:Peptide Chain Initiation, Translational / Q000235:genetics; D010445:Peptide Elongation Factors / Q000235:genetics / Q000378:metabolism; D011233:Precipitin Tests; D016196:S Phase / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D003432:Cross-Linking Reagents; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C076365:MCM10 protein, S cerevisiae; D009687:Nuclear Proteins; D051738:Origin Recognition Complex; D010445:Peptide Elongation Factors; D029701:Saccharomyces cerevisiae Proteins; D064110:Minichromosome Maintenance Proteins