Abstract
The MCM2-MCM7 complex is an essential component of the prereplication complex (pre-RC), which is recruited by the cdc6 and cdt1 proteins to origins of DNA replication during G(1) phase. Here, we report that the accumulation on chromatin of another member of the MCM protein family, human MCM8 (hMCM8), occurs during early G(1) phase, before the hMCM2-hMCM7 complex binds. hMCM8 interacts in vivo with two components of the pre-RC, namely, hcdc6 and hORC2. Depletion of endogenous hMCM8 protein by RNA interference leads to a delay of entry into S phase, suggesting a role for hMCM8 in G(1) progression. Furthermore, down-regulation of hMCM8 also leads to a reduced loading of hcdc6 and the hMCM2-hMCM7 complex on chromatin. These results suggest that hMCM8 is a crucial component of the pre-RC and that the interaction between hMCM8 and hcdc6 is required for pre-RC assembly.
MeSH terms
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cells, Cultured
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Chromatin / genetics
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Chromatin / metabolism*
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DNA Replication / genetics*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Flow Cytometry
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HeLa Cells
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Humans
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Minichromosome Maintenance Complex Component 2
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Minichromosome Maintenance Complex Component 7
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Minichromosome Maintenance Proteins
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Origin Recognition Complex
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Protein Binding / genetics
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism
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S Phase / genetics*
Substances
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CDC6 protein, human
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Cell Cycle Proteins
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Chromatin
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DNA-Binding Proteins
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Nuclear Proteins
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Origin Recognition Complex
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RNA, Small Interfering
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MCM2 protein, human
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MCM7 protein, human
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MCM8 protein, human
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Minichromosome Maintenance Complex Component 2
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Minichromosome Maintenance Complex Component 7
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Minichromosome Maintenance Proteins