Chinese hamster ORC subunits dynamically associate with chromatin throughout the cell-cycle

McNairn, Adrian J.; Okuno, Yukiko; Misteli, Tom; Gilbert, David M.

doi:10.1016/j.yexcr.2005.05.009

Cited by 37 publications

(46 citation statements)

References 83 publications

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“…A similar dynamic behavior was also reported for ORC components (45). In contrast, a recent study showed stable binding of MCM proteins to chromatin in CHO cells (48).…”

Section: A System For Studying MCM Protein Dynamics Within Livesupporting

confidence: 83%

“…We have estimated an apparent residence time of 1-2 h on the basis of FLIP analysis, whereas earlier work indicated even longer residence times for MCM proteins in Chinese hamster ovary cells (48). In contrast, other components of the prereplication complex, such as ORC (45) and Cdt1 (46,47), dissociate completely from chromatin within seconds or minutes. This is consistent with in vitro work in Xenopus egg (63) and yeast extracts (64,65) that showed that the MCM hexamer can be stably loaded on chromatin, whereas ORC and Cdt1 can be subsequently washed away.…”

Section: Discussionmentioning

confidence: 88%

See 1 more Smart Citation

Multi-step Loading of Human Minichromosome Maintenance Proteins in Live Human Cells

Symeonidou

Kotsantis

Roukos

et al. 2013

Journal of Biological Chemistry

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Background: MCM2-7 loading onto chromatin licenses origins for replication. Results: MCMs exhibit transient interactions with chromatin in late mitosis, stable binding in G 1 phase and increased loading in late G 1 phase. Conclusion: Multilevel regulation of MCM2-7 loading to chromatin occurs during mitosis and preceding the G 1 /S phase transition. Significance: The dynamics of the DNA licensing system within live human cells reveal multiple control points.

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“…A similar dynamic behavior was also reported for ORC components (45). In contrast, a recent study showed stable binding of MCM proteins to chromatin in CHO cells (48).…”

Section: A System For Studying MCM Protein Dynamics Within Livesupporting

confidence: 83%

Section: Discussionmentioning

confidence: 88%

Multi-step Loading of Human Minichromosome Maintenance Proteins in Live Human Cells

Symeonidou

Kotsantis

Roukos

et al. 2013

Journal of Biological Chemistry

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show abstract

“…The degradation of ORC1 may not be a consistent regulatory feature, as it is observed in some cells but not in others. [18][19][20] The importance of Cdc6 nuclear export is controversial due to conflicting reports on the extent of nuclear export, as described below. Overexpression of a non-degradable Cdt1 produces limited DNA re-replication (significantly less than in fission yeast).…”

Section: The Prevention Of Dna Re-replication In Yeast and Metazoansmentioning

confidence: 99%

Control of the Cdc6 replication licensing factor in metazoa: The role of nuclear export and the CUL4 ubiquitin ligase

Kim¹,

Kipreos²

2008

Cell Cycle

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“…These and other studies suggest that, while the protein levels and chromatin association of Orc2-6 remain constant throughout the cell cycle, Orc1 is selectively removed following origin activation until the next cell cycle. However, it is not clear how the biochemical or cytological behavior of the bulk population of ORC contributes to DNA replication regulation (34).…”

mentioning

confidence: 99%

CDK Phosphorylation Inhibits the DNA-binding and ATP-hydrolysis Activities of the Drosophila Origin Recognition Complex

Remus¹,

Blanchette²,

Rio

et al. 2005

Journal of Biological Chemistry

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Faithful propagation of eukaryotic chromosomes usually requires that no DNA segment be replicated more than once during one cell cycle. Cyclin-dependent kinases (Cdks) are critical for the re-replication controls that inhibit the activities of components of the pre-replication complexes (pre-RCs) following origin activation. The origin recognition complex (ORC) initiates the assembly of pre-RCs at origins of replication and Cdk phosphorylation of ORC is important for the prevention of re-initiation. Here we show that Drosophila melanogaster ORC (DmORC) is phosphorylated in vivo and is a substrate for Cdks in vitro. Cdk phosphorylation of DmORC subunits DmOrc1p and DmOrc2p inhibits the intrinsic ATPase activity of DmORC without affecting ATP binding to DmOrc1p. Moreover, Cdk phosphorylation inhibits the ATP-dependent DNA-binding activity of DmORC in vitro, thus identifying a novel determinant for DmORC-DNA interaction. DmORC is a substrate for both Cdk2⅐cyclin E and Cdk1⅐cyclin B in vitro. Such phosphorylation of DmORC by Cdk2⅐cyclin E, but not by Cdk1⅐cyclin B, requires an "RXL" motif in DmOrc1p. We also identify casein kinase 2 (CK2) as a kinase activity in embryonic extracts targeting DmORC for modification. CK2 phosphorylation does not affect ATP hydrolysis by DmORC but modulates the ATP-dependent DNA-binding activity of DmORC. These results suggest molecular mechanisms by which Cdks may inhibit ORC function as part of re-replication control and show that DmORC activity may be modulated in response to phosphorylation by multiple kinases.Prevention of re-replication in eukaryotic cells is essential for the maintenance of genomic ploidy, and mechanisms preventing such reinitiation-associated events are needed because unscheduled or uncontrolled DNA replication initiation can lead to genomic instability (1-5). Re-replication control is achieved through (i) the prevention of repeated origin firing during one S phase and (ii) coordination of chromosomal replication with the segregation of the sister chromatids in mitosis. Genetic studies in the fission yeast Schizosaccharomyces pombe first demonstrated that cyclin-dependent kinases (Cdks) 4 play a prominent role in preventing re-replication during S phase and coupling S phase progression to chromosomal segregation in mitosis, by showing that inhibition of Cdk activity in G 2 /M can induce re-entry into S phase in the absence of mitosis (6 -8). Additional studies in the budding yeast, Saccharomyces cerevisiae, substantiated these findings and demonstrated that some Cdk activity is required for one round of replication and that higher levels accumulating in S phase prevent re-initiation. Thus Cdks have both negative and positive roles in the initiation of DNA replication (9). It is now known that in all eukaryotes studied Cdks contribute to the prevention of re-replication through direct inactivation of pre-RC proteins via multiple redundant mechanisms. This redundancy ensures that deregulation of any single mechanism is not sufficient to induce genomic re-replica...

show abstract

Chinese hamster ORC subunits dynamically associate with chromatin throughout the cell-cycle

Cited by 37 publications

References 83 publications

Multi-step Loading of Human Minichromosome Maintenance Proteins in Live Human Cells

Multi-step Loading of Human Minichromosome Maintenance Proteins in Live Human Cells

Control of the Cdc6 replication licensing factor in metazoa: The role of nuclear export and the CUL4 ubiquitin ligase

CDK Phosphorylation Inhibits the DNA-binding and ATP-hydrolysis Activities of the Drosophila Origin Recognition Complex

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