Eukaryotic Replication Origins and Initiation of DNA Replication

Abstract

Eukaryotic deoxyribonucleic acid (DNA) replication begins at specific genomic sites called replication origins that serve as assembly sites for prereplication complexes (preRCs). PreRCs include proteins that recognise origin sequences, helicases that separate the two strands of DNA and accessory proteins that facilitate helicase binding and interaction with cell cycle regulatory pathways. Assembly of preRCs is required for initiation of DNA replication which occurs after those complexes recruit additional proteins including DNA polymerases. The sequence requirements for replication origins vary but they all include several distinct DNA elements that act synergistically to facilitate preRC assembly. The number of potential replication origins is higher than the number of actual replication initiation sites. Epigenetic processes and metabolic conditions dynamically select the location of replication initiation events of each cell cycle to insure complete and accurate replication of the entire genome in coordination with gene expression and chromatin condensation.

Key Concepts:

  • Replication initiates at distinct chromosomal locations that recruit prereplication (preRC) complexes.

  • PreRCs are recruited sequentially, each step subject to strict regulation to prevent rereplication.

  • Cyclin‐dependent kinases (CDK) levels change during the cell cycle. Low CDK activity is required for preRC assembly as cells exit mitosis. High CDK activity is required for activation of existing preRCs and initiation of DNA synthesis, while simultaneously suppressing assembly of new preRCs.

  • Replication origin sequences vary among metazoans, but the functions of proteins that bind replication origins are conserved.

  • Eukaryotic origins exhibit a modular structure. Modularity is detectable in single‐cell eukaryotes such as yeast and is more pronounced in metazoans, in which replication origins often cluster.

  • Not all potential replication origins are activated in each cell cycle. Utilisation of replication origins is regulated dynamically to facilitate coordination with other metabolic processes occurring on chromatin.

  • Either hyperactivation or suppression of replication origins can damage DNA and cause chromosomal rearrangements, suggesting that spacing replication initiation events at defined intervals facilitates genomic stability.

Keywords: ARS; DNA synthesis; origin recognition proteins; ORC; cell division cycle proteins; Mcm proteins; DNA unwinding; prereplication complex; preinitiation complex; replicator

Figure 1.

Basic organisation of replication origins. Red indicates sequence elements that are required under all conditions (core components), whereas yellow indicates sequence elements (transcription factor‐binding sites) that facilitate replication under some conditions (auxiliary components). Arrows indicate protein:protein interactions. Origins contain an A:T‐rich element (A/T) with adenines on one strand and thymines on the other, an (ORE) and a DNA‐unwinding element (DUE).

Figure 2.

Assembly and activation of prereplication complexes. Reproduced from Aladjem , with permission from Nature Publishing Group.

Figure 3.

Molecular interaction map of the initiation of DNA replication. An interactive version of the map can be found at http://discover.nci.nih.gov/mim. Annotations for the Molecular Interaction Map (an interactive version can be found online: http://discover.nci.nih.gov/mim/).

ORC, the origin recognition complex, is a complex of six subunits. ORC binds chromosomal sites that are capable of initiating DNA replication. In yeast cells, ORC recognises autonomous replicating sequences (ARS elements; Bell and Stillman, ) in an (ATP)‐dependent manner (Klemm et al., ). ORC orthologues were found in other eukaryotes, including mammals (Gavin et al., ), but the DNA sequence or structural requirements for mammalian ORC binding had not been elucidated yet. In Drosophila, ORC binds the chorion gene replication origin, ACE3 (Austin et al., ).

ORC1 associates less tightly than other subunits in the formation of the ORC complex (Saha et al., ). In Xenopus, it may leave the complex during S phase (Rowles et al., ; Natale et al., ); similar observations suggest that this also happens in mammals (Kreitz et al., ; Méndez and Stillman, ).

ORC1 is phosphorylated by Cyclin A and Cyclin B complexes (Ohtani et al., ; Wolf et al., ). ORC1 is ubiquitinated and released from chromatin during S phase (Li and DePamphilis, ).

ORC2–4 form a tight complex (Ishiai et al., ; Quintana et al., ). ORC2 and 3 may form a tighter complex that binds ORC4 (Vashee et al., ). The ORC2–4 complex localises to chromatin depending on E2F (E2 transcription factor) in Drosophila (Austin et al., ). The ORC2–4 complex is hyperphosphorylated on ORC2 at M phase (Carpenter et al., ; Carpenter and Dunphy, ).

ORC5 forms a complex with ORC2–4 (Ishiai et al., ; Quintana et al., ; Vashee et al., ). ORC5 directly interacts with CDC6 in yeast (Liang et al., ).

ORC6 probably binds only weakly to the other ORC subunits (Vashee et al., ). The presence of ORC6 in the prereplication complex (preRC) depends on E2F, as E2F mutants fail to include the ORC6 in the complex (Hateboer et al., ).

Two complexes of ORC subunits can bind DNA:ORC1–6 and ORC2–6. In mammalian cells, ORC1 leaves chromatin after initiation of DNA replication (see interaction 2 for details).

ORC2 phosphorylation inhibits initiation of DNA replication (Carpenter et al., ; Carpenter and Dunphy, ).

CDC6 binds to the ORC:DNA complex at the beginning of G1 and leaves the complex before G1/S (Saha et al., ). CDC6 is essential for DNA replication in Xenopus (Williams et al., ). In S. pombe, initiation of DNA replication depends on the presence of CDC6 before the end of G1, but not after the activation of CDKs (Coleman et al., ). CDC6 interacts directly with ORC (Bell et al., ). In Xenopus, it localises near origins (Romanowski et al., ).

CDC6 is phosphorylated primarily by Cyclin A:CDK2 (Brown et al., ; Lopez‐Girona et al., ) and Cyclin E:CDK2 (Jiang et al., ). Phosphorylation localises CDC6 to the cytoplasm (Jallepalli et al., ; Jiang et al., ; Delmolino et al., ; Ishimi et al., ) and probably targets CDC6 for ubiquitination (Jallepalli and Kelly, ). CDC6 binds Cyclin E (Petersen et al., ). Phosphorylated CDC6 is transported from the nucleus to the cytoplasm, preventing licensing during S phase (Ishimi et al., ).

CDT1 is part of the preRC. Cdt binding to preRC is essential for loading MCMs to create the preRC (Maiorano et al., ).

CDT1 binding to the ORC complex requires prior binding of CDC6 to the complex (Maiorano et al., ).

Geminin binds CDT1 (Wohlschlegel et al., ) and degrades it to prevent loading of MCMs to chromatin (McGarry and Kirschner, ).

The MCM complex, a helicase, is known as a part of the ‘licensing’ complex (Maine et al., ). Binding of the MCM complex to the ORC complex on chromatin constitutes the preRC which confers competence for initiation of DNA replication. MCMs associate with origin‐specific DNA before initiation of DNA replication; after replication, the association becomes nonspecific (Aparicio et al., ; Tanaka et al., ). In yeast, MCM–chromatin association depends on CDC6 (Donovan et al., ; Ogawa et al., ).

MCM4, 6 and7 are tightly bound to each other (Musahl et al., ), loosely bound to the other MCM proteins. This complex exhibits helicase activity (not shown; Ishimi et al., ).

MCM4 is phosphorylated by Cyclin B:CDK1 in Xenopus (Hendrickson et al., ) and humans (Todorov et al., ; no clear evidence for the kinase identity in human cells, but the same phosphorylation sites as in Xenopus imply that the kinases are the same). Some phosphorylation activity was observed with Cyclin A:CDK1 (Ishimi et al., ).

Phosphorylation of MCM4 reduces the affinity of the MCM complex to chromatin and reduces the helicase activity of the MCM complex (Hendrickson et al., ).

MCM3 forms a tight complex with MCM5 (Kimura et al., ; Schulte et al., ). MCM3/MCM5 forms a looser complex with the other MCM proteins (Sherman et al., ).

MCM2 loosely associated with the MCM4, 6 and 7, complex (Sherman et al., ).

MCM2 is a target of phosphorylation by a kinase family that includes Cdc7 in yeast and hsk1 (homolog of cdc seven kinase 1) in humans (Jiang et al., ; Masai et al., ; Lei et al., ; Oshiro et al., ; Weinreich et al., ). Phosphorylation facilitates binding of MCM2 to other MCM subunits (see interaction 21).

MCM2 phosphorylation by Cdc7 type kinases (Cdc7:DBF4 in yeast, hsk/dpf4 in humans) facilitates binding of MCM2 to other MCM subunits and initiation of DNA replication (Masai et al., ).

MCM10 associates with DNA polymerase alpha. MCM10:DNA polymerase alpha associate with MCM2–7 and chromatin in humans (Izumi et al., ). MCM10 is required for assembly of the preRC in S. cerevisiae (Homesley et al., ), Xenopus (Walter, ; Jares and Blow, ) and human cells. Binding of MCM10 to chromatin seems to occur throughout the cell cycle (Izumi et al., ; Lee et al., ).

Cdc45 incorporates into the preRC (Zou and Stillman, ) and is essential for initiation of DNA replication in yeast. Cdc45 co‐immunoprecipitates with MCMs (Hopwood and Dalton, ). In yeast, Cdc45 interacts with MCMs (Hennessy et al., ) and ORC2 (Aparicio et al., ; Zou and Stillman, ), and its association with DNA depends on CDC6 and MCM (Zou and Stillman, ; Aparicio et al., ). Cdc45 binding to chromatin, but not Cdc45 transcription, requires an active E2F in Drosophila (Arata et al., ). Chromatin binding is inhibited by the DNA damage checkpoint (Costanzo et al., ).

Binding of Cdc45 to the ORC:MCM complex on chromatin necessitates two kinase complexes: S phase Cyclin:CDK, especially Cyclin E:CDK2, and homologs of yeast Cdc7:DBF4 (DDK‐hsk1 in humans). The yeast homologue of Cyclin E:CDK2 was shown to be required for Cdc45 binding to chromatin in yeast (Zou and Stillman, ); Cdc7:DBF4 was shown to be also necessary (Nougarède et al., ; Zou and Stillman, ). Cdc7:DBF4 was shown directly to phosphorylate Cdc45.

Double‐stranded breaks inhibit the addition of Cdc45 to the preinitiation complex (ORC:MCM:Cdc7) in Xenopus extracts. This inhibition depends on the activity of the (ATM) kinase (Costanzo et al., ). ATM‐dependent activation of MreI:nbs:Rad50 complex can also inhibit progression through S phase, but this activation does not inhibit binding of Cdc45 to chromatin (Falck et al., ).

Cdc45 immunoprecipitates with origin DNA before initiation, but binds nonspecifically to DNA after initiation of DNA replication (Aparicio et al., ). Cdc45 interacts with DNA polymerase alpha (Mimura and Takisawa, ) and HsCdc45 associates with ORC2 (Saha et al., ).

MCM10, possibly in complex with DNA polymerase alpha, binds to the chromatin‐bound MCM complex and this binding is essential for recruitment of Cdc45 to the preinitiation complex (Lee et al., ).

Cyclin‐dependent kinases can phosphorylate various components of the licensing and initiation pathways as a complex with their appropriate cyclin partners. Cyclins are synthesised at specific times during the cell cycle and regulate kinase activities. These interactions are inhibited by phosphorylation of the kinases which can be relieved by phosphatases of the Cdc25 family (see interaction 43) or by small molecule inhibitors such as p21 (see interactions 29, 30 and 33).

CDK2 can bind either Cyclin A or Cyclin E. For details on activation of CDK2, see Kohn .

Cdc2 (CDK1), in association with either Cyclin B or Cyclin A, phosphorylates ORC2. Phosphorylation inhibits initiation of DNA replication. Cyclin B:Cdc2 phosphorylates ORC in vitro, and probably prevents replication during mitosis (Kelly and Brown, ). In S. pombe, ORC2 is phosphorylated by Cdc2 (Lygerou and Nurse, ) and phosphorylation helps prevent reinitiation (Vas et al., ). Cyclin A:Cdc2 binds ORC and phosphorylates ORC2p in Xenopus (Romanowski et al., ).

Cyclin B:CDK1 complexes are mitotic complexes. These kinase complexes phosphorylate MCM4, an inhibitory phosphorylation which reduces binding of the MCM complex to chromatin (Hendrickson et al., ).

Cyclin B1:CDK1 phosphorylates ORC1 and ORC2 during mitosis (Ohtani et al., ; Wolf et al., ; Kelly and Brown, ).

The transcription factor p53 facilitates the synthesis of various molecules involved in cellular response to genotoxic conditions. Among others, it facilitates transcription of the cyclin‐dependent kinase inhibitor p21, gadd45 and molecules involved in apoptosis. For details, see Kohn .

During interphase, the activity of the Cyclin B:CDK1 complex is inhibited by the phosphorylation of CDK1 on Thr 14 and Thr 15 by Wee1 (Parker and Piwnica‐Worms, ).

CDK2, in combination with its cyclin partners, phosphorylates Cdc45 and facilitates its binding to licensed DNA in concert with another phosphorylation mediated by hsk1/dpf4 (Nougarède et al., ).

CDK2, in combination with its cyclin partners, phosphorylates CDC6 and targets it for transport to the cytoplasm and degradation (Brown et al., ; Lopez‐Girona et al., ; Jiang et al., ; Ishimi et al., ).

Cyclin A:CDK2 phosphorylates ORC1 (Findeisen et al., ).

Inhibition of DNA replication by the DNA topoisomerase I inhibitor camptothecin, or by UV irradiation activates the ATR ()‐dependent pathway of the S phase checkpoint (Guo et al., ). The first step in the pathway is the binding of ATR to its partner ATRIP ()

Checkpoint kinase 2 (CHK2) is phosphorylated after replication arrest by ATR, the homologue of yeast Rad3/Mec1 (Boddy et al., ; Sun et al., ; Lindsay et al., ). Rad3/Mec2 is required for in vitro phosphorylation of cds1 (Martinho et al., ). In yeast, cds1 is involved in the mitosis checkpoint: regulates phosphorylation of CDKs, Cyclin B:CDK1 through Wee and Mik (Enoch and Nurse, ; Rhind and Russell, ; Lundgren et al., ).

Phosphorylation of Wee1 by CHK1 on Ser549 enhances its ability to bind 14‐3‐3 proteins during interphase (not shown) and increases kinase activity of Wee1 (Lee et al., ). Kinase activity during interphase guards against premature activation of the mitotic Cyclin:CDK complexes (e.g. Cyclin B:CDK1) and prevents mitotic entry as a part of the G2/M checkpoint. For more details on Wee1 interactions see Kohn .

CHK1 phosphorylates Cdc25A in response to DNA damage (Furnari et al., ; Peng et al., ).

Phosphorylation of Cdc25A leads to its exclusion from the nucleus in yeast (Zeng et al., ; Peng et al., ). The phosphorylated protein cannot activate the mitotic Cyclin B:CDK1 complex (Lopez‐Girona et al., ; Zeng and Piwnica‐Worms, ).

Cdc25A phosphatase activity is required for activation of CDKs (Hoffmann et al. ; Jinno et al., ). CHK2‐mediated phosphorylation following irradiation and activation by ATM leads to degradation of Cdc25A (Falck et al., ).

Double‐stranded DNA breaks trigger the signal transduction cascade, whose first step is phosphorylation by the ATM kinase. These phosphorylation steps lead to inhibition of further initiation of DNA replication on licensed DNA by inhibiting the hsk1/dpf4 and the cyclin‐dependent kinases (see interactions 47–49), and may trigger apoptosis through the p53‐mediated pathway (see interaction 50). There is also some evidence that ATM may directly inhibit binding of Cdc45 to licensed chromatin (see interaction 45).

ATM may directly inhibit binding of Cdc45 to licensed chromatin through a pathway that does not involve the inhibitor Cdc25A to disallow cyclin‐dependent kinase activity (Falck et al., ).

ATM phosphorylates p53 in response to DNA damage (Banin et al., ; Tibbetts et al., ). This phosphorylation may lead to p53‐mediated apoptosis. For details see Kohn .

HsCds1/CHK2 is phosphorylated after irradiation, and formation of DNA strand breaks, but not after treatment with the drug hydroxyurea (Matsuoka et al., ; Brown et al., ).

CHK2 phosphorylates Cdc25A after DNA damage (Furnari et al., ; Ford et al., ; Peng et al., ).

Hsk1/dpf4 is the human orthologue of yeast Cdc7:DBF4. Cdc7:DBF4 is required for the onset of replication in yeast and prevention of reassembly of preRC on origins (Bousset and Diffley, ; Schwob et al., ; Dahmann et al., ; Piatti et al., ). DBF4 is the regulatory protein; its expression levels regulate Cdc7 activity (Brown et al., ). The DBF4 mouse homologue interacts with MCM2 (Lepke et al., ).

Hsk1:dfp1 phosphorylates MCM2 (Lei et al., ) and Cdc45 (Zou and Stillman, ).

Binding of MCM10 to dfp1 facilitates kinase activity of hsk1 (Lee et al., ).

Activation of the S phase checkpoint in Xenopus inhibits hsk1:dfp1 kinase activity through a mechanism which requires ATR (Costanzo et al., ).

Auto‐phosphorylation of hsk1 inhibits the activity of the hsk1:dfp1 complex (Izumi et al., ).

MCM10 is phosphorylated in G2/M, and this phosphorylation leads to its degradation (Izumi et al., ).

DNA damage or potential genotoxic conditions trigger the signal transduction cascade mediated by the transcription factor p53. For details, see reference Kohn .

SLD3 is recruited to licensed replication origins, interacting with the MCM complex (Kanemaki and Labib, ; Yabuuchi et al., ).

SLD3 loading on chromatin requires Cdc7‐DBF4 (Yabuuchi et al., ).

SLD3 recruits GINS complex to licensed origins (Kanemaki and Labib, ; Yabuuchi et al., ).

SLD3 interacts with Cdc45; both proteins associate with early origins during G1 and with late origins during late S phase in yeast (Kamimura et al., ).

CDKs phosphorylate SLD3 (Zegerman and Diffley, ).

CDKs phosphorylate SLD2 (Zegerman and Diffley, ).

Phosphorylation of SLD2 and SLD3 is required for initiation of DNA replication (Liu et al., ; Zegerman and Diffley, ).

SLD3 loading on chromatin is required for GINS loading (Takayama et al., ).

After phosphorylatoin by CDKs, SLD3 binds DPB11 (orthologue of TOPBP1) in yeast; Liu et al., ; Zegerman and Diffley, ); similar results were obtained in Xenopus (Hashimoto and Takisawa, ).

SLD2 interacts with DPB11 in yeast (Kamimura et al., ).

Phosphorylation of SLD2 by CDKs is essential for initiation (Masumoto et al., ).

Association of TOPBP1 and phosphorylation of SLD2 and SLD3 by CDKs are essential for recruitment of Cdc45 to chromatin (the cited works only mention TOPBP1 recruitement and CDK activity and do not specify the SLDs; Hashimoto and Takisawa, ).

MCM10 recruits polymerase alpha to chromatin for initiation (Ricke and Bielinsky, ; Zhu et al., ) and is involved in regulation of replication elongation as well as initiation (Chattopadhyay and Bielinsky, ).

MCM10 association with chromatin is required for the phosphorylation of MCMs by Cdc7 (Lee et al., ).

MCM10 chromatin association stimulates binding of Cdc45 (Wohlschlegel et al., ).

GINS maintains association of Cdc45 with MCMs during elongation (Gambus et al., ).

TOPBP1 is involved in recruitment of Cdc45 to chromatin (Schmidt et al., ).

Polo‐like kinase is required for Cdc45 loading on chromatin (Trenz et al., ).

GINS loading on chromatin, presumably via the MCM complex, is essential for loading Cdc45 (Takayama et al., ).

GINS interaction with Cdc45 is required for Cdc45 loading on chromatin (Yabuuchi et al., ).

Figure 4.

Replication origins that function in eukaryotic cells. The Simian virus 40 (SV40) core origin (64 bp) consists of an origin recognition element (ORE) that is required for T‐antigen binding, an easily unwound sequence (, DUE) where DNA unwinding begins and an A:T‐rich element containing adenines on one strand and thymines on the other. Together these components occupy ∼160 bp of DNA and exhibit (ARS) activity. Auxiliary elements bind a T‐antigen dimer (aux‐1) and transcription factor Sp1 (aux‐2). The spacing and orientation of these elements are critical and therefore represent a rigid modular anatomy. Replication origins in the budding yeast Saccharomyces cerevisiae consist of 100–150 bp that exhibit ARS activity. Origins consist of two core elements (A and B1) that occupy ∼43 bp and constitute the binding site for the six‐protein origin recognition complex (ORC), and a DUE that generally contains a genetically defined B2 element. Some origins also contain an auxiliary element (B3) that binds transcription factor Abf‐1. Each element is interchangeable with homologous elements from other S. cerevisiae origins and therefore exhibits a flexible modular anatomy. Yeast origins are context sensitive. Replication origins in the fission yeast S. pombe consist of at least one ARS element that is 0.5–1 kb in size. In some cases, multiple ARS elements in close proximity form an initiation zone in which replication bubbles appear to occur randomly, but in fact, originate from specific ARS elements. Whether or not S. pombe origins exhibit a modular anatomy is not yet known. In mammalian cells, some origins consist of a large intergenic initiation zone (shaded region) defined by two‐dimensional gel origin‐mapping methods and one or more high‐frequency initiation sites (OBRs) defined by nascent strand origin‐mapping methods (e.g. the dhfr and rrna gene regions). Other origins such as the Lamin B2 gene region consist of a single OBR that exhibits a cell cycle‐dependent DNA footprint (ORC?) reminiscent of those at S. cerevisiae origins. The Lamin B2 origin also overlaps three transcription factor‐binding sites belonging to the promoter of a downstream gene. Initiation events in the intergenic region (0.6 kb) downstream of the Lamin B gene have not been analysed by two‐dimensional gel analysis.

close

References

Aladjem MI (2007) Replication in context: dynamic regulation of DNA replication patterns in metazoans. Nature Reviews. Genetics 8(8): 588–600.

Aladjem MI, Groudine M, Brody LL et al. (1995) Participation of the human beta‐globin locus control region in initiation of DNA replication. Science 270(5237): 815–819.

Anglana M, Apiou F, Bensimon A and Debatisse M (2003) Dynamics of DNA replication in mammalian somatic cells: nucleotide pool modulates origin choice and interorigin spacing. Cell 114(3): 385–394.

Aparicio JG, Viggiani CJ, Gibson DG and Aparicio OM (2004) The Rpd3‐Sin3 histone deacetylase regulates replication timing and enables intra‐S origin control in Saccharomyces cerevisiae. Molecular and Cellular Biology 24(11): 4769–4780.

Aparicio OM, Weinstein DM and Bell SP (1997) Components and dynamics of DNA replication complexes in S. cerevisiae: redistribution of MCM proteins and Cdc45p during S phase. Cell 91(1): 59–69.

Aparicio T, Guillou E, Coloma J, Montoya G and Mendez J (2009) The human GINS complex associates with Cdc45 and MCM and is essential for DNA replication. Nucleic Acids Research 37(7): 2087–2095.

Arata Y, Fujita M, Ohtani K, Kijima S and Kato JY (2000) Cdk2‐dependent and ‐independent pathways in E2F‐mediated S phase induction. The Journal of Biological Chemistry 275(9): 6337–6345.

Austin RJ, Orr‐Weaver TL and Bell SP (1999) Drosophila ORC specifically binds to ACE3, an origin of DNA replication control element. Genes and Development 13(20): 2639–2649.

Banin S, Moyal L, Shieh S et al. (1998) Enhanced phosphorylation of p53 by ATM in response to DNA damage. Science 281(5383): 1674–1677.

Bell SP (2002) The origin recognition complex: from simple origins to complex functions. Genes and Development 16(6): 659–672.

Bell SP, Kobayashi R and Stillman B (1993) Yeast origin recognition complex functions in transcription silencing and DNA replication. Science 262(5141): 1844–1849.

Bell SP and Stillman B (1992) ATP‐dependent recognition of eukaryotic origins of DNA replication by a multiprotein complex. Nature 357(6374): 128–134.

Boddy MN, Furnari B, Mondesert O and Russell P (1998) Replication checkpoint enforced by kinases Cds1 and Chk1. Science 280(5365): 909–912.

Boskovic J, Coloma J, Aparicio T et al. (2007) Molecular architecture of the human GINS complex. EMBO Reports 8(7): 678–684.

Bousset K and Diffley JF (1998) The Cdc7 protein kinase is required for origin firing during S phase. Genes and Development 12(4): 480–490.

Brown AL, Lee CH, Schwarz JK et al. (1999) A human Cds1‐related kinase that functions downstream of ATM protein in the cellular response to DNA damage. Proceedings of the National Academy of Sciences of the USA 96(7): 3745–3750.

Brown GW, Jallepalli PV, Huneycutt BJ and Kelly TJ (1997) Interaction of the S phase regulator cdc18 with cyclin‐dependent kinase in fission yeast. Proceedings of the National Academy of Sciences of the USA 94(12): 6142–6147.

Cadoret JC, Meisch F, Hassan‐Zadeh V et al. (2008) Genome‐wide studies highlight indirect links between human replication origins and gene regulation. Proceedings of the National Academy of Sciences of the USA 105(41): 15837–15842.

Carpenter PB and Dunphy WG (1998) Identification of a novel 81‐kDa component of the Xenopus origin recognition complex. The Journal of Biological Chemistry 273(38): 24891–24897.

Carpenter PB, Mueller PR and Dunphy WG (1996) Role for a Xenopus Orc2‐related protein in controlling DNA replication. Nature 379(6563): 357–360.

Chattopadhyay S and Bielinsky AK (2007) Human Mcm10 regulates the catalytic subunit of DNA polymerase‐alpha and prevents DNA damage during replication. Molecular Biology of the Cell 18(10): 4085–4095.

Coleman TR, Carpenter PB and Dunphy WG (1996) The Xenopus Cdc6 protein is essential for the initiation of a single round of DNA replication in cell‐free extracts. Cell 87(1): 53–63.

Costanzo V, Robertson K, Ying CY et al. (2000) Reconstitution of an ATM‐dependent checkpoint that inhibits chromosomal DNA replication following DNA damage. Molecular Cell 6(3): 649–659.

Costanzo V, Shechter D, Lupardus PJ et al. (2003) An ATR‐ and Cdc7‐dependent DNA damage checkpoint that inhibits initiation of DNA replication. Molecular Cell 11(1): 203–213.

Dahmann C, Diffley JF and Nasmyth KA (1995) S‐phase‐promoting cyclin‐dependent kinases prevent re‐replication by inhibiting the transition of replication origins to a pre‐replicative state. Current Biology 5(11): 1257–1269.

Danis E, Brodolin K, Menut S et al. (2004) Specification of a DNA replication origin by a transcription complex. Nature Cell Biology 6(8): 721–730.

Delmolino LM, Saha P and Dutta A (2001) Multiple mechanisms regulate subcellular localization of human CDC6. The Journal of Biological Chemistry 276(29): 26947–26954.

DePamphilis ML (1993) Origins of DNA replication in metazoan chromosomes. The Journal of Biological Chemistry 268(1): 1–4.

DePamphilis ML (1999) Replication origins in metazoan chromosomes: fact or fiction? Bioessays 21(1): 5–16.

Dershowitz A, Snyder M, Sbia M et al. (2007) Linear derivatives of Saccharomyces cerevisiae chromosome III can be maintained in the absence of autonomously replicating sequence elements. Molecular and Cellular Biology 27(13): 4652–4663.

Donovan S, Harwood J, Drury LS and Diffley JF (1997) Cdc6p‐dependent loading of Mcm proteins onto pre‐replicative chromatin in budding yeast. Proceedings of the National Academy of Sciences of the USA 94(11): 5611–5616.

Donti TR, Datta S, Sandoval PY and Kapler GM (2009) Differential targeting of Tetrahymena ORC to ribosomal DNA and non‐rDNA replication origins. The EMBO Journal 28(3): 223–233.

Dubey DD, Zhu J, Carlson DL, Sharma K and Huberman JA (1994) Three ARS elements contribute to the ura4 replication origin region in the fission yeast, Schizosaccharomyces pombe. The EMBO Journal 13(15): 3638–3647.

Enoch T and Nurse P (1990) Mutation of fission yeast cell cycle control genes abolishes dependence of mitosis on DNA replication. Cell 60(4): 665–673.

Falck J, Mailand N, Syljuåsen RG, Bartek J and Lukas J (2001) The ATM‐Chk2‐Cdc25A checkpoint pathway guards against radioresistant DNA synthesis. Nature 410(6830): 842–847.

Falck J, Petrini JH, Williams BR, Lukas J and Bartek J (2002) The DNA damage‐dependent intra‐S phase checkpoint is regulated by parallel pathways. Nature Genetics 30(3): 290–294.

Fanning E and Zhao K (2009) SV40 DNA replication: from the A gene to a nanomachine. Virology 384(2): 352–359.

Findeisen M, El‐Denary M, Kapitza T, Graf R and Strausfeld U (1999) Cyclin A‐dependent kinase activity affects chromatin binding of ORC, Cdc6, and MCM in egg extracts of Xenopus laevis. European Journal of Biochemistry 264(2): 415–426.

Ford JC, al‐Khodairy F, Fotou E et al. (1994) 14‐3‐3 protein homologs required for the DNA damage checkpoint in fission yeast. Science 265(5171): 533–535.

Fu H, Wang L, Lin CM et al. (2006) Preventing gene silencing with human replicators. Nature Biotechnology 24(5): 572–576.

Furnari B, Blasina A, Boddy MN, McGowan CH and Russell P (1999) Cdc25 inhibited in vivo and in vitro by checkpoint kinases Cds1 and Chk1. Molecular Biology of the Cell 10(4): 833–845.

Gambus A, Jones RC, Sanchez‐Diaz A et al. (2006) GINS maintains association of Cdc45 with MCM in replisome progression complexes at eukaryotic DNA replication forks. Nature Cell Biology 8(4): 358–366.

Gavin KA, Hidaka M and Stillman B (1995) Conserved initiator proteins in eukaryotes. Science 270(5242): 1667–1671.

Gilbert DM, Miyazawa H and DePamphilis ML (1995) Site‐specific initiation of DNA replication in Xenopus egg extract requires nuclear structure. Molecular and Cellular Biology 15(6): 2942–2954.

Gomez M and Brockdorff N (2004) Heterochromatin on the inactive X chromosome delays replication timing without affecting origin usage. Proceedings of the National Academy of Sciences of the USA 101(18): 6923–6928.

Gregoire D, Brodolin K and Mechali M (2006) HoxB domain induction silences DNA replication origins in the locus and specifies a single origin at its boundary. EMBO Reports 7(8): 812–816.

Guo Z, Kumagai A, Wang SX and Dunphy WG (2000) Requirement for Atr in phosphorylation of Chk1 and cell cycle regulation in response to DNA replication blocks and UV‐damaged DNA in Xenopus egg extracts. Genes and Development 14(21): 2745–2756.

Hashimoto Y and Takisawa H (2003) Xenopus Cut5 is essential for a CDK‐dependent process in the initiation of DNA replication. The EMBO Journal 22(10): 2526–2535.

Hateboer G, Wobst A, Petersen BO et al. (1998) Cell cycle‐regulated expression of mammalian CDC6 is dependent on E2F. Molecular and Cellular Biology 18(11): 6679–6697.

Hendrickson M, Madine M, Dalton S and Gautier J (1996) Phosphorylation of MCM4 by cdc2 protein kinase inhibits the activity of the minichromosome maintenance complex. Proceedings of the National Academy of Sciences of the USA 93(22): 12223–12228.

Hennessy KM, Lee A, Chen E and Botstein D (1991) A group of interacting yeast DNA replication genes. Genes and Development 5(6): 958–969.

Hoffmann I, Draetta G and Karsenti E (1994) Activation of the phosphatase activity of human cdc25A by a cdk2‐cyclin E dependent phosphorylation at the G1/S transition. The EMBO Journal 13(18): 4302–4310.

Homesley L, Lei M, Kawasaki Y et al. (2000) Mcm10 and the MCM2‐7 complex interact to initiate DNA synthesis and to release replication factors from origins. Genes and Development 14(8): 913–926.

Hopwood B and Dalton S (1996) Cdc45p assembles into a complex with Cdc46p/Mcm5p, is required for minichromosome maintenance, and is essential for chromosomal DNA replication. Proceedings of the National Academy of Sciences of the USA 93(22): 12309–12314.

Huang D and Koshland D (2003) Chromosome integrity in Saccharomyces cerevisiae: the interplay of DNA replication initiation factors, elongation factors, and origins. Genes and Development 17(14): 1741–1754.

Hyrien O, Maric C and Mechali M (1995) Transition in specification of embryonic metazoan DNA replication origins. Science 270(5238): 994–997.

Ishiai M, Dean FB, Okumura K et al. (1997) Isolation of human and fission yeast homologues of the budding yeast origin recognition complex subunit ORC5: human homologue (ORC5L) maps to 7q22. Genomics 46(2): 294–298.

Ishimi Y, Ichinose S, Omori A, Sato K and Kimura H (1996) Binding of human minichromosome maintenance proteins with histone H3. The Journal of Biological Chemistry 271(39): 24115–24122.

Ishimi Y, Komamura‐Koh no Y, You Z, Omori A and Kitagawa M (2000) Inhibition of Mcm4,6,7 helicase activity by phosphorylation with cyclin A/Cdk2. The Journal of Biological Chemistry 275(21): 16235–16241.

Izumi M, Yanagi K, Mizuno T et al. (2000) The human homolog of Saccharomyces cerevisiae Mcm10 interacts with replication factors and dissociates from nuclease‐resistant nuclear structures in G(2) phase. Nucleic Acids Research 28(23): 4769–4777.

Izumi M, Yatagai F and Hanaoka F (2001) Cell cycle‐dependent proteolysis and phosphorylation of human Mcm10. The Journal of Biological Chemistry 276(51): 48526–48531.

Jacob F, Brenner J and Cuzin F (1963) On the regulation of DNA replication in bacteria. Cold Spring Harbor Symposia on Quantitative Biology 28: 329.

Jallepalli PV and Kelly TJ (1996) Rum1 and Cdc18 link inhibition of cyclin‐dependent kinase to the initiation of DNA replication in Schizosaccharomyces pombe. Genes and Development 10(5): 541–552.

Jallepalli PV, Tien D and Kelly TJ (1998) sud1(+) targets cyclin‐dependent kinase‐phosphorylated Cdc18 and Rum1 proteins for degradation and stops unwanted diploidization in fission yeast. Proceedings of the National Academy of Sciences of the USA 95(14): 8159–8164.

Jares P and Blow JJ (2000) Xenopus cdc7 function is dependent on licensing but not on XORC, XCdc6, or CDK activity and is required for XCdc45 loading. Genes and Development 14(12): 1528–1540.

Jiang W, Wells NJ and Hunter T (1999) Multistep regulation of DNA replication by Cdk phosphorylation of HsCdc6. Proceedings of the National Academy of Sciences of the USA 96(11): 6193–6198.

Jinno S, Suto K, Nagata A et al. (1994) Cdc25A is a novel phosphatase functioning early in the cell cycle. The EMBO Journal 13(7): 1549–1556.

Kalejta RF, Li X, Mesner LD et al. (1998) Distal sequences, but not ori‐beta/OBR‐1, are essential for initiation of DNA replication in the Chinese hamster DHFR origin. Molecular Cell 2(6): 797–806.

Kamimura Y, Masumoto H, Sugino A and Araki H (1998) Sld2, which interacts with Dpb11 in Saccharomyces cerevisiae, is required for chromosomal DNA replication. Molecular and Cellular Biology 18(10): 6102–6109.

Kamimura Y, Tak YS, Sugino A and Araki H (2001) Sld3, which interacts with Cdc45 (Sld4), functions for chromosomal DNA replication in Saccharomyces cerevisiae. The EMBO Journal 20(8): 2097–2107.

Kanemaki M and Labib K (2006) Distinct roles for Sld3 and GINS during establishment and progression of eukaryotic DNA replication forks. The EMBO Journal 25(8): 1753–1763.

Karnani N, Taylor CM, Malhotra A and Dutta A (2010) Genomic study of replication initiation in human chromosomes reveals the influence of transcription regulation and chromatin structure on origin selection. Molecular Biology of the Cell 21: 393–404.

Kelly TJ and Brown GW (2000) Regulation of chromosome replication. Annual Review of Biochemistry 69: 829–880.

Kim SM and Huberman JA (1998) Multiple orientation‐dependent, synergistically interacting, similar domains in the ribosomal DNA replication origin of the fission yeast, Schizosaccharomyces pombe. Molecular and Cellular Biology 18(12): 7294–7303.

Kimura H, Takizawa N, Nozaki N and Sugimoto K (1995) Molecular cloning of cDNA encoding mouse Cdc21 and CDC46 homologs and characterization of the products: physical interaction between P1(MCM3) and CDC46 proteins. Nucleic Acids Research 23(12): 2097–2104.

Klemm RD, Austin RJ and Bell SP (1997) Coordinate binding of ATP and origin DNA regulates the ATPase activity of the origin recognition complex. Cell 88(4): 493–502.

Kohn KW (1999) Molecular interaction map of the mammalian cell cycle control and DNA repair systems. Molecular Biology of the Cell 10(8): 2703–2734.

Kreitz S, Ritzi M, Baack M and Knippers R (2001) The human origin recognition complex protein 1 dissociates from chromatin during S phase in HeLa cells. The Journal of Biological Chemistry 276(9): 6337–6342.

Kumagai A, Shevchenko A and Dunphy WG (2010) Treslin collaborates with TopBP1 in triggering the initiation of DNA replication. Cell 140(3): 349–359.

Lee J, Kumagai A and Dunphy WG (2001) Positive regulation of Wee1 by Chk1 and 14‐3‐3 proteins. Molecular Biology of the Cell 12(3): 551–563.

Lee JK, Seo YS and Hurwitz J (2003) The Cdc23 (Mcm10) protein is required for the phosphorylation of minichromosome maintenance complex by the Dfp1‐Hsk1 kinase. Proceedings of the National Academy of Sciences of the USA 100(5): 2334–2339.

Lei M, Kawasaki Y, Young MR et al. (1997) Mcm2 is a target of regulation by Cdc7‐Dbf4 during the initiation of DNA synthesis. Genes and Development 11(24): 3365–3374.

Lengronne A and Schwob E (2002) The yeast CDK inhibitor Sic1 prevents genomic instability by promoting replication origin licensing in late G(1). Molecular Cell 9(5): 1067–1078.

Lepke M, Pütter V, Staib C et al. (1999) Identification, characterization and chromosomal localization of the cognate human and murine DBF4 genes. Molecular and General Genetics 262(2): 220–229.

Li CJ and DePamphilis ML (2002) Mammalian Orc1 protein is selectively released from chromatin and ubiquitinated during the S‐to‐M transition in the cell division cycle. Molecular and Cellular Biology 22(1): 105–116.

Liang C, Weinreich M and Stillman B (1995) ORC and Cdc6p interact and determine the frequency of initiation of DNA replication in the genome. Cell 81(5): 667–676.

Lin CM, Fu H, Martinovsky M, Bouhassira E and Aladjem MI (2003) Dynamic alterations of replication timing in mammalian cells. Current Biology 13(12): 1019–1028.

Lindsay HD, Griffiths DJ, Edwards RJ et al. (1998) S‐phase‐specific activation of Cds1 kinase defines a subpathway of the checkpoint response in Schizosaccharomyces pombe. Genes and Development 12(3): 382–395.

Liu K, Luo Y, Lin FT and Lin WC (2004) TopBP1 recruits Brg1/Brm to repress E2F1‐induced apoptosis, a novel pRb‐independent and E2F1‐specific control for cell survival. Genes and Development 18(6): 673–686.

Lopez‐Girona A, Furnari B, Mondesert O and Russell P (1999) Nuclear localization of Cdc25 is regulated by DNA damage and a 14‐3‐3 protein. Nature 397(6715): 172–175.

Lopez‐Girona A, Mondesert O, Leatherwood J and Russell P (1998) Negative regulation of Cdc18 DNA replication protein by Cdc2. Molecular Biology of the Cell 9(1): 63–73.

Lundgren K, Walworth N, Booher R et al. (1991) mik1 and wee1 cooperate in the inhibitory tyrosine phosphorylation of cdc2. Cell 64(6): 1111–1122.

Lygerou Z and Nurse P (1999) The fission yeast origin recognition complex is constitutively associated with chromatin and is differentially modified through the cell cycle. Journal of Cell Science 112(part 21): 3703–3712.

Maine GT, Sinha P and Tye BK (1984) Mutants of S. cerevisiae defective in the maintenance of minichromosomes. Genetics 106(3): 365–385.

Maiorano D, Moreau J and Méchali M (2000) XCDT1 is required for the assembly of pre‐replicative complexes in Xenopus laevis. Nature 404(6778): 622–625.

Martinho RG, Lindsay HD, Flaggs G et al. (1998) Analysis of Rad3 and Chk1 protein kinases defines different checkpoint responses. The EMBO Journal 17(24): 7239–7249.

Masai H, Matsui E, You Z et al. (2000) Human Cdc7‐related kinase complex. In vitro phosphorylation of MCM by concerted actions of Cdks and Cdc7 and that of a critical threonine residue of Cdc7 bY Cdks. The Journal of Biological Chemistry 275(37): 29042–29052.

Masumoto H, Muramatsu S, Kamimura Y and Araki H (2002) S‐Cdk‐dependent phosphorylation of Sld2 essential for chromosomal DNA replication in budding yeast. Nature 415(6872): 651–655.

Matsuoka S, Huang M and Elledge SJ (1998) Linkage of ATM to cell cycle regulation by the Chk2 protein kinase. Science 282(5395): 1893–1897.

McGarry TJ and Kirschner MW (1998) Geminin, an inhibitor of DNA replication, is degraded during mitosis. Cell 93(6): 1043–1053.

Méchali M and Kearsey S (1984) Lack of specific sequence requirement for DNA replication in Xenopus eggs compared with high sequence specificity in yeast. Cell 38: 55–64.

Méndez J and Stillman B (2000) Chromatin association of human origin recognition complex, cdc6, and minichromosome maintenance proteins during the cell cycle: assembly of prereplication complexes in late mitosis. Molecular and Cellular Biology 20(22): 8602–8612.

Mimura S and Takisawa H (1998) Xenopus Cdc45‐dependent loading of DNA polymerase alpha onto chromatin under the control of S‐phase Cdk. The EMBO Journal 17(19): 5699–5707.

Mohammad MM, Donti TR, Sebastian Yakisich J, Smith AG and Kapler GM (2007) Tetrahymena ORC contains a ribosomal RNA fragment that participates in rDNA origin recognition. The EMBO Journal 26(24): 5048–5060.

Musahl C, Schulte D, Burkhart R and Knippers R (1995) A human homologue of the yeast replication protein Cdc21. Interactions with other Mcm proteins. European Journal of Biochemistry 230(3): 1096–1101.

Natale DA, Li CJ, Sun WH and DePamphilis ML (2000) Selective instability of Orc1 protein accounts for the absence of functional origin recognition complexes during the M‐G(1) transition in mammals. The EMBO Journal 19(11): 2728–2738.

Nougarède R, Della Seta F, Zarzov P and Schwob E (2000) Hierarchy of S‐phase‐promoting factors: yeast Dbf4‐Cdc7 kinase requires prior S‐phase cyclin‐dependent kinase activation. Molecular and Cellular Biology 20(11): 3795–3806.

Ogawa Y, Takahashi T and Masukata H (1999) Association of fission yeast Orp1 and Mcm6 proteins with chromosomal replication origins. Molecular and Cellular Biology 19(10): 7228–7236.

Ohtani K, DeGregori J, Leone G et al. (1996) Expression of the HsOrc1 gene, a human ORC1 homolog, is regulated by cell proliferation via the E2F transcription factor. Molecular and Cellular Biology 16(12): 6977–6984.

Oshiro G, Owens JC, Shellman Y, Sclafani RA and Li JJ (1999) Cell cycle control of Cdc7p kinase activity through regulation of Dbf4p stability. Molecular and Cellular Biology 19(7): 4888–4896.

Palacios DeBeer MA, Muller U and Fox CA (2003) Differential DNA affinity specifies roles for the origin recognition complex in budding yeast heterochromatin. Genes and Development 17(15): 1817–1822.

Parker LL and Piwnica‐Worms H (1992) Inactivation of the p34cdc2‐cyclin B complex by the human WEE1 tyrosine kinase. Science 257(5078): 1955–1957.

Peng CY, Graves PR, Thoma RS et al. (1997) Mitotic and G2 checkpoint control: regulation of 14‐3‐3 protein binding by phosphorylation of Cdc25C on serine‐216. Science 277(5331): 1501–1505.

Petersen BO, Lukas J, Sørensen CS, Bartek J and Helin K (1999) Phosphorylation of mammalian CDC6 by cyclin A/CDK2 regulates its subcellular localization. The EMBO Journal 18(2): 396–410.

Piatti PM, Monti LD, Valsecchi G et al. (1996) Effects of low‐dose heparin infusion on arterial endothelin‐1 release in humans. Circulation 94(11): 2703–2707.

Quintana DG, Hou Zh, Thome KC et al. (1997) Identification of HsORC4, a member of the human origin of replication recognition complex. The Journal of Biological Chemistry 272(45): 28247–28251.

Raghuraman MK, Winzeler EA, Collingwood D et al. (2001) Replication dynamics of the yeast genome. Science 294(5540): 115–121.

Rein T, Kobayashi T, Malott M, Leffak M and DePamphilis ML (1999) DNA methylation at mammalian replication origins. The Journal of Biological Chemistry 274(36): 25792–25800.

Remus D, Beall EL and Botchan MR (2004) DNA topology, not DNA sequence, is a critical determinant for Drosophila ORC‐DNA binding. The EMBO Journal 23(4): 897–907.

Remus D and Diffley JF (2009) Eukaryotic DNA replication control: lock and load, then fire. Current Opinion in Cell Biology 21(6): 771–777.

Rhind N and Russell P (1998) The Schizosaccharomyces pombe S‐phase checkpoint differentiates between different types of DNA damage. Genetics 149(4): 1729–1737.

Ricke RM and Bielinsky AK (2004) Mcm10 regulates the stability and chromatin association of DNA polymerase‐alpha. Molecular Cell 16(2): 173–185.

Romanowski P, Madine MA, Rowles A, Blow JJ and Laskey RA (1996) The Xenopus origin recognition complex is essential for DNA replication and MCM binding to chromatin. Current Biology 6(11): 1416–1425.

Romanowski P, Marr J, Madine MA et al. (2000) Interaction of Xenopus Cdc2 x cyclin A1 with the origin recognition complex. The Journal of Biological Chemistry 275(6): 4239–4243.

Rowles A, Chong JP, Brown L et al. (1996) Interaction between the origin recognition complex and the replication licensing system in Xenopus. Cell 87(2): 287–296.

Saha P, Chen J, Thome KC et al. (1998) Human CDC6/Cdc18 associates with Orc1 and cyclin‐cdk and is selectively eliminated from the nucleus at the onset of S phase. Molecular and Cellular Biology 18(5): 2758–2767.

Saha S, Shan Y, Mesner LD and Hamlin JL (2004) The promoter of the Chinese hamster ovary dihydrofolate reductase gene regulates the activity of the local origin and helps define its boundaries. Genes and Development 18(4): 397–410.

Schmidt U, Wollmann Y, Franke C et al. (2008) Characterization of the interaction between the human DNA topoisomerase IIbeta‐binding protein 1 (TopBP1) and the cell division cycle 45 (Cdc45) protein. The Biochemical Journal 409(1): 169–177.

Schulte D, Richter A, Burkhart R, Musahl C and Knippers R (1996) Properties of the human nuclear protein p85Mcm. Expression, nuclear localization and interaction with other Mcm proteins. European Journal of Biochemistry 235(1 and 2): 144–151.

Schwob E, Böhm T, Mendenhall MD and Nasmyth K (1994) The B‐type cyclin kinase inhibitor p40SIC1 controls the G1 to S transition in S. cerevisiae. Cell 79(2): 233–244.

Sherman DA, Pasion SG and Forsburg SL (1998) Multiple domains of fission yeast Cdc19p (MCM2) are required for its association with the core MCM complex. Molecular Biology of the Cell 9(7): 1833–1845.

Sheu YJ and Stillman B (2010) The Dbf4‐Cdc7 kinase promotes S phase by alleviating an inhibitory activity in Mcm4. Nature 463(7277): 113–117.

Shirahige K, Hori Y, Shiraishi K et al. (1998) Regulation of DNA‐replication origins during cell‐cycle progression. Nature 395(6702): 618–621.

Stanojcic S, Lemaitre JM, Brodolin K, Danis E and Mechali M (2008) In Xenopus egg extracts, DNA replication initiates preferentially at or near asymmetric AT sequences. Molecular and Cellular Biology 28(17): 5265–5274.

Sun Z, Fay DS, Marini F, Foiani M and Stern DF (1996) Spk1/Rad53 is regulated by Mec1‐dependent protein phosphorylation in DNA replication and damage checkpoint pathways. Genes and Development 10(4): 395–406.

Takayama Y, Kamimura Y, Okawa M et al. (2003) GINS, a novel multiprotein complex required for chromosomal DNA replication in budding yeast. Genes and Development 17(9): 1153–1165.

Tanaka T, Knapp D and Nasmyth K (1997) Loading of an Mcm protein onto DNA replication origins is regulated by Cdc6p and CDKs. Cell 90(4): 649–660.

Tibbetts RS, Brumbaugh KM, Williams JM et al. (1999) A role for ATR in the DNA damage‐induced phosphorylation of p53. Genes and Development 13(2): 152–157.

Todorov IT, Attaran A and Kearsey SE (1995) BM28, a human member of the MCM2‐3‐5 family, is displaced from chromatin during DNA replication. The Journal of Cell Biology 129(6): 1433–1445.

Trenz K, Errico A and Costanzo V (2008) Plx1 is required for chromosomal DNA replication under stressful conditions. The EMBO Journal 27(6): 876–885.

Vas A, Mok W and Leatherwood J (2001) Control of DNA rereplication via Cdc2 phosphorylation sites in the origin recognition complex. Molecular and Cellular Biology 21(17): 5767–5777.

Vashee S, Simancek P, Challberg MD and Kelly TJ (2001) Assembly of the human origin recognition complex. The Journal of Biological Chemistry 276(28): 26666–26673.

Vogelauer M, Rubbi L, Lucas I, Brewer BJ and Grunstein M (2002) Histone acetylation regulates the time of replication origin firing. Molecular Cell 10(5): 1223–1233.

Walter JC (2000) Evidence for sequential action of cdc7 and cdk2 protein kinases during initiation of DNA replication in Xenopus egg extracts. The Journal of Biological Chemistry 275(50): 39773–39778.

Weinreich M, Liang C and Stillman B (1999) The Cdc6p nucleotide‐binding motif is required for loading mcm proteins onto chromatin. Proceedings of the National Academy of Sciences of the USA 96(2): 441–446.

Williams RS, Shohet RV and Stillman B (1997) A human protein related to yeast Cdc6p. Proceedings of the National Academy of Sciences of the USA 94(1): 142–147.

Wohlschlegel JA, Dhar SK, Prokhorova TA, Dutta A and Walter JC (2002) Xenopus Mcm10 binds to origins of DNA replication after Mcm2‐7 and stimulates origin binding of Cdc45. Molecular Cell 9(2): 233–240.

Wohlschlegel JA, Dwyer BT, Dhar SK et al. (2000) Inhibition of eukaryotic DNA replication by geminin binding to Cdt1. Science 290(5500): 2309–2312.

Wolf DA, Wu D and McKeon F (1996) Disruption of re‐replication control by overexpression of human ORC1 in fission yeast. The Journal of Biological Chemistry 271(51): 32503–32506.

Wu JR and Gilbert DM (1996) A distinct G1 step required to specify the Chinese hamster DHFR replication origin. Science 271(5253): 1270–1272.

Wu PY and Nurse P (2009) Establishing the program of origin firing during S phase in fission yeast. Cell 136(5): 852–864.

Wyrick JJ, Aparicio JG, Chen T et al. (2001) Genome‐wide distribution of ORC and MCM proteins in S. cerevisiae: high‐resolution mapping of replication origins. Science 294(5550): 2357–2360.

Yabuuchi H, Yamada Y, Uchida T et al. (2006) Ordered assembly of Sld3, GINS and Cdc45 is distinctly regulated by DDK and CDK for activation of replication origins. The EMBO Journal 25(19): 4663–4674.

Zegerman P and Diffley JF (2007) Phosphorylation of Sld2 and Sld3 by cyclin‐dependent kinases promotes DNA replication in budding yeast. Nature 445(7125): 281–285.

Zeng Y, Forbes KC, Wu Z et al. (1998) Replication checkpoint requires phosphorylation of the phosphatase Cdc25 by Cds1 or Chk1. Nature 395(6701): 507–510.

Zeng Y and Piwnica‐Worms H (1999) DNA damage and replication checkpoints in fission yeast require nuclear exclusion of the Cdc25 phosphatase via 14‐3‐3 binding. Molecular and Cellular Biology 19(11): 7410–7419.

Zhou J, Ashouian N, Delepine M et al. (2002) The origin of a developmentally regulated Igh replicon is located near the border of regulatory domains for Igh replication and expression. Proceedings of the National Academy of Sciences of the USA 99(21): 13693–13698.

Zhu W, Ukomadu C, Jha S et al. (2007) Mcm10 and And‐1/CTF4 recruit DNA polymerase alpha to chromatin for initiation of DNA replication. Genes and Development 21(18): 2288–2299.

Zou L and Stillman B (1998) Formation of a preinitiation complex by S‐phase cyclin CDK‐dependent loading of Cdc45p onto chromatin. Science 280(5363): 593–596.

Zou L and Stillman B (2000) Assembly of a complex containing Cdc45p, replication protein A, and Mcm2p at replication origins control led by S‐phase cyclin‐dependent kinases and Cdc7p‐Dbf4p kinase. Molecular and Cellular Biology 20(9): 3086–3096.

Further Reading

Antequera F (2004) Genomic specification and epigenetic regulation of eukaryotic DNA replication origins. The EMBO Journal 23: 4365–4370.

Blow JJ and Gillespie PJ (2008) Replication licensing and cancer – a fatal entanglement? Nature Reviews. Cancer 8: 799–806.

Donaldson AD (2005) Shaping time: chromatin structure and the DNA replication programme. Trends in Genetics 21: 444–449.

Machida YJ, Hamlin JL and Dutta A (2005) Right place, right time, and only once: replication initiation in metazoans. Cell 123: 13–24.

Sclafani RA and Holzen TM (2007) Cell cycle regulation of DNA replication. Annual Review of Genetics 41: 237–280.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
DePamphilis, Melvin L, and Aladjem, Mirit I(Sep 2010) Eukaryotic Replication Origins and Initiation of DNA Replication. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0001055.pub2]