Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
During late mitosis and early G(1), a series of proteins are assembled onto replication origins, resulting in them becoming 'licensed' for replication in the subsequent S phase. Four factors have so far been identified that are required for chromatin to become functionally licensed: ORC (the origin recognition complex) and Cdc6, plus the two components of the replication licensing system RLF-M and RLF-B. Here we describe the first steps of a systematic fractionation of Xenopus egg extracts to identify all the components necessary for the assembly of licensed replication origins on Xenopus sperm nuclei (the physiological DNA substrate in this system). We have purified a new activity essential for this reaction, and have shown that it is nucleoplasmin, a previously known chromatin remodelling protein. Nucleoplasmin decondenses the sperm chromatin by removing protamines, and is required at the earliest known step in origin assembly to allow ORC to bind to the DNA. Sperm nuclei can be licensed by a combination of nucleoplasmin, RLF-M and a partially purified fraction that contains ORC, Cdc6 and RLF-B. This suggests that we are likely to have identified most of the proteins required for this assembly reaction.
Barry,
Swelling of hen erythrocyte nuclei in cytoplasm from Xenopus eggs.
1972, Pubmed,
Xenbase
Barry,
Swelling of hen erythrocyte nuclei in cytoplasm from Xenopus eggs.
1972,
Pubmed
,
Xenbase
Bell,
ATP-dependent recognition of eukaryotic origins of DNA replication by a multiprotein complex.
1992,
Pubmed
Blow,
A role for the nuclear envelope in controlling DNA replication within the cell cycle.
1988,
Pubmed
,
Xenbase
Blow,
A cdc2-like protein is involved in the initiation of DNA replication in Xenopus egg extracts.
1990,
Pubmed
,
Xenbase
Blow,
Preventing re-replication of DNA in a single cell cycle: evidence for a replication licensing factor.
1993,
Pubmed
,
Xenbase
Blow,
Initiation of DNA replication in nuclei and purified DNA by a cell-free extract of Xenopus eggs.
1986,
Pubmed
,
Xenbase
Carpenter,
Role for a Xenopus Orc2-related protein in controlling DNA replication.
1996,
Pubmed
,
Xenbase
Chong,
Purification of an MCM-containing complex as a component of the DNA replication licensing system.
1995,
Pubmed
,
Xenbase
Chong,
The role of MCM/P1 proteins in the licensing of DNA replication.
1996,
Pubmed
Chong,
Characterization of the Xenopus replication licensing system.
1997,
Pubmed
,
Xenbase
Coleman,
The Xenopus Cdc6 protein is essential for the initiation of a single round of DNA replication in cell-free extracts.
1996,
Pubmed
,
Xenbase
Diffley,
Two steps in the assembly of complexes at yeast replication origins in vivo.
1994,
Pubmed
,
Xenbase
Diffley,
Once and only once upon a time: specifying and regulating origins of DNA replication in eukaryotic cells.
1996,
Pubmed
Dilworth,
Two complexes that contain histones are required for nucleosome assembly in vitro: role of nucleoplasmin and N1 in Xenopus egg extracts.
1987,
Pubmed
,
Xenbase
Dimitrov,
Remodeling somatic nuclei in Xenopus laevis egg extracts: molecular mechanisms for the selective release of histones H1 and H1(0) from chromatin and the acquisition of transcriptional competence.
1996,
Pubmed
,
Xenbase
Dingwall,
Nucleoplasmin: the archetypal molecular chaperone.
1990,
Pubmed
,
Xenbase
Dingwall,
A polypeptide domain that specifies migration of nucleoplasmin into the nucleus.
1982,
Pubmed
,
Xenbase
Donovan,
Cdc6p-dependent loading of Mcm proteins onto pre-replicative chromatin in budding yeast.
1997,
Pubmed
,
Xenbase
Fang,
Evidence that the G1-S and G2-M transitions are controlled by different cdc2 proteins in higher eukaryotes.
1991,
Pubmed
,
Xenbase
Harland,
Regulated replication of DNA microinjected into eggs of Xenopus laevis.
1980,
Pubmed
,
Xenbase
Hua,
Identification of a preinitiation step in DNA replication that is independent of origin recognition complex and cdc6, but dependent on cdk2.
1998,
Pubmed
,
Xenbase
Hyrien,
Plasmid replication in Xenopus eggs and egg extracts: a 2D gel electrophoretic analysis.
1992,
Pubmed
,
Xenbase
Hyrien,
Chromosomal replication initiates and terminates at random sequences but at regular intervals in the ribosomal DNA of Xenopus early embryos.
1993,
Pubmed
,
Xenbase
Ishimi,
Binding of human minichromosome maintenance proteins with histone H3.
1996,
Pubmed
Kearsey,
MCM proteins: evolution, properties, and role in DNA replication.
1998,
Pubmed
Kleinschmidt,
Nucleosome assembly in vitro: separate histone transfer and synergistic interaction of native histone complexes purified from nuclei of Xenopus laevis oocytes.
1990,
Pubmed
,
Xenbase
Kleinschmidt,
Soluble acidic complexes containing histones H3 and H4 in nuclei of Xenopus laevis oocytes.
1982,
Pubmed
,
Xenbase
Kleinschmidt,
Co-existence of two different types of soluble histone complexes in nuclei of Xenopus laevis oocytes.
1985,
Pubmed
,
Xenbase
Kubota,
Determination of initiation of DNA replication before and after nuclear formation in Xenopus egg cell free extracts.
1993,
Pubmed
,
Xenbase
Kubota,
Identification of the yeast MCM3-related protein as a component of Xenopus DNA replication licensing factor.
1995,
Pubmed
,
Xenbase
Kubota,
Licensing of DNA replication by a multi-protein complex of MCM/P1 proteins in Xenopus eggs.
1997,
Pubmed
,
Xenbase
Laskey,
Nucleosomes are assembled by an acidic protein which binds histones and transfers them to DNA.
1978,
Pubmed
,
Xenbase
Leno,
Hyperphosphorylation of nucleoplasmin facilitates Xenopus sperm decondensation at fertilization.
1996,
Pubmed
,
Xenbase
Liang,
Persistent initiation of DNA replication and chromatin-bound MCM proteins during the cell cycle in cdc6 mutants.
1997,
Pubmed
Lu,
Histone H1 modulates DNA replication through multiple pathways in Xenopus egg extract.
1997,
Pubmed
,
Xenbase
Lu,
Histone H1 reduces the frequency of initiation in Xenopus egg extract by limiting the assembly of prereplication complexes on sperm chromatin.
1998,
Pubmed
,
Xenbase
Mahbubani,
DNA replication initiates at multiple sites on plasmid DNA in Xenopus egg extracts.
1992,
Pubmed
,
Xenbase
Mahbubani,
Cell cycle regulation of the replication licensing system: involvement of a Cdk-dependent inhibitor.
1997,
Pubmed
,
Xenbase
Mann,
Characterization of spermatid/sperm basic chromosomal proteins in the genus Xenopus (Anura, Pipidae).
1982,
Pubmed
,
Xenbase
McGarry,
Geminin, an inhibitor of DNA replication, is degraded during mitosis.
1998,
Pubmed
,
Xenbase
Mills,
An acidic protein which assembles nucleosomes in vitro is the most abundant protein in Xenopus oocyte nuclei.
1980,
Pubmed
,
Xenbase
Nelson,
Ribonucleic acid and other polyanions facilitate chromatin assembly in vitro.
1981,
Pubmed
Nishitani,
p65cdc18 plays a major role controlling the initiation of DNA replication in fission yeast.
1995,
Pubmed
Philpott,
Sperm decondensation in Xenopus egg cytoplasm is mediated by nucleoplasmin.
1991,
Pubmed
,
Xenbase
Philpott,
Nucleoplasmin remodels sperm chromatin in Xenopus egg extracts.
1992,
Pubmed
,
Xenbase
Prokhorova,
Sequential MCM/P1 subcomplex assembly is required to form a heterohexamer with replication licensing activity.
2000,
Pubmed
,
Xenbase
Romanowski,
The Xenopus origin recognition complex is essential for DNA replication and MCM binding to chromatin.
1996,
Pubmed
,
Xenbase
Rowles,
Changes in association of the Xenopus origin recognition complex with chromatin on licensing of replication origins.
1999,
Pubmed
,
Xenbase
Rowles,
Interaction between the origin recognition complex and the replication licensing system in Xenopus.
1996,
Pubmed
,
Xenbase
Sealy,
Xenopus nucleoplasmin: egg vs. oocyte.
1986,
Pubmed
,
Xenbase
Stein,
Acidic polypeptides can assemble both histones and chromatin in vitro at physiological ionic strength.
1979,
Pubmed
Strausfeld,
Cip1 blocks the initiation of DNA replication in Xenopus extracts by inhibition of cyclin-dependent kinases.
1994,
Pubmed
,
Xenbase
Tada,
The replication licensing system.
1998,
Pubmed
,
Xenbase
Tada,
The RLF-B component of the replication licensing system is distinct from Cdc6 and functions after Cdc6 binds to chromatin.
1999,
Pubmed
,
Xenbase
Thömmes,
The RLF-M component of the replication licensing system forms complexes containing all six MCM/P1 polypeptides.
1997,
Pubmed
,
Xenbase
