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Undiluted extracts from eggs or oocytes of Xenopus laevis support the assembly of chromatin with physiologically spaced nucleosomes. Micrococcal nuclease and DNase I digestion experiments show that nucleosome formation as well as supercoiling of circular DNA concomitant to assembly do not require ATP or Mg2+. However these factors are essential for the stability and the physiological spacing of the assembled chromatin. gamma-S-ATP can substitute for ATP in this process. With topoisomers of defined linking number topological interconversions proceed by steps of unity, both in vitro as well as in vivo, indicating that topoisomerase I is dominantly acting in this process. Novobiocin sensitivity occurred only with diluted extracts and was unrelated to an inhibition of topoisomerase II. Finally, nucleosome assembly occurs efficiently on linear DNA although the assembled DNA is less stable than with circular DNA. From these results we propose that mature chromatin is formed in a two-step reaction. In the first step, nucleosome deposition occurs independently of ATP and Mg2+. Thus, nucleosome formation can be uncoupled from their spacing. In this step, topoisomerase activity is involved in the relaxation of the topological constraints generated by chromatin assembly rather than in the process of assembly itself. The second step, requiring ATP and Mg2+, generates properly spaced chromatin.
Adamson,
Histone synthesis in early amphibian development: histone and DNA syntheses are not co-ordinated.
1974, Pubmed,
Xenbase
Adamson,
Histone synthesis in early amphibian development: histone and DNA syntheses are not co-ordinated.
1974,
Pubmed
,
Xenbase
Anderson,
Supercoiling in closed circular DNA: dependence upon ion type and concentration.
1978,
Pubmed
Attardi,
Purification and characterization of Xenopus laevis type I topoisomerase.
1981,
Pubmed
,
Xenbase
Axel,
Cleavage of DNA in nuclei and chromatin with staphylococcal nuclease.
1975,
Pubmed
Axel,
Specific sites of interaction between histones and DNA in chromatin.
1974,
Pubmed
Bakayev,
Nucleosomes and subnucleosomes: heterogeneity and composition.
1977,
Pubmed
Benedetti,
Purification and characterization of Xenopus laevis topoisomerase II.
1983,
Pubmed
,
Xenbase
Benyajati,
Isolation, characterization, and structure of the folded interphase genome of Drosophila melanogaster.
1976,
Pubmed
Burke,
A cell free system to study reassembly of the nuclear envelope at the end of mitosis.
1986,
Pubmed
Camerini-Otero,
The organization of histones and DNA in chromatin: evidence for an arginine-rich histone kernel.
1976,
Pubmed
Cande,
Nucleotide requirements for anaphase chromosome movements in permeabilized mitotic cells: anaphase B but not anaphase A requires ATP.
1982,
Pubmed
Castora,
ATP inhibits nuclear and mitochondrial type I topoisomerases from human leukemia cells.
1986,
Pubmed
Chen,
Nonintercalative antitumor drugs interfere with the breakage-reunion reaction of mammalian DNA topoisomerase II.
1984,
Pubmed
Cook,
Characterization of nuclear structures containing superhelical DNA.
1976,
Pubmed
Cotten,
Novobiocin precipitates histones at concentrations normally used to inhibit eukaryotic type II topoisomerase.
1986,
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
Dumont,
Oogenesis in Xenopus laevis (Daudin). I. Stages of oocyte development in laboratory maintained animals.
1972,
Pubmed
,
Xenbase
Earnshaw,
Assembly of nucleosomes: the reaction involving X. laevis nucleoplasmin.
1980,
Pubmed
,
Xenbase
Eissenberg,
Selected topics in chromatin structure.
1985,
Pubmed
Gargiulo,
Analysis of the chromatin assembled in germinal vesicles of Xenopus oocytes.
1983,
Pubmed
,
Xenbase
Gellert,
DNA topoisomerases.
1981,
Pubmed
Germond,
Folding of the DNA double helix in chromatin-like structures from simian virus 40.
1975,
Pubmed
Glikin,
Chromatin assembly in Xenopus oocytes: in vitro studies.
1984,
Pubmed
,
Xenbase
Gurdon,
Injected nuclei in frog oocytes: fate, enlargement, and chromatin dispersal.
1976,
Pubmed
,
Xenbase
Gurdon,
The use of Xenopus oocytes for the expression of cloned genes.
1983,
Pubmed
,
Xenbase
Horowitz,
Torsional rigidity of DNA and length dependence of the free energy of DNA supercoiling.
1984,
Pubmed
Hsiang,
Camptothecin induces protein-linked DNA breaks via mammalian DNA topoisomerase I.
1985,
Pubmed
Hsieh,
ATP-dependent DNA topoisonmerase from D. melanogaster reversibly catenates duplex DNA rings.
1980,
Pubmed
Laskey,
Assembly of SV40 chromatin in a cell-free system from Xenopus eggs.
1977,
Pubmed
,
Xenbase
Laskey,
Chromosome replication in early Xenopus embryos.
1985,
Pubmed
,
Xenbase
Lohka,
Formation in vitro of sperm pronuclei and mitotic chromosomes induced by amphibian ooplasmic components.
1983,
Pubmed
,
Xenbase
Low,
Inhibition of HeLa cell DNA topoisomerase I by ATP and phosphate.
1985,
Pubmed
Lutter,
Precise location of DNase I cutting sites in the nucleosome core determined by high resolution gel electrophoresis.
1979,
Pubmed
Marini,
Decatenation of kinetoplast DNA by topoisomerases.
1980,
Pubmed
Mattoccia,
DNA-relaxing activity and endonuclease activity in Xenopus laevis oocytes.
1976,
Pubmed
,
Xenbase
Maxam,
A new method for sequencing DNA.
1977,
Pubmed
Méchali,
DNA synthesis in a cell-free system from Xenopus eggs: priming and elongation on single-stranded DNA in vitro.
1982,
Pubmed
,
Xenbase
Méchali,
Tumor promoter TPA increases initiation of replication on DNA injected into xenopus eggs.
1983,
Pubmed
,
Xenbase
Mertz,
Linear DNA does not form chromatin containing regularly spaced nucleosomes.
1982,
Pubmed
,
Xenbase
Nelson,
Extracts of Drosophila embryos mediate chromatin assembly in vitro.
1979,
Pubmed
Newport,
Nuclear reconstitution in vitro: stages of assembly around protein-free DNA.
1987,
Pubmed
,
Xenbase
Newport,
A major developmental transition in early Xenopus embryos: II. Control of the onset of transcription.
1982,
Pubmed
,
Xenbase
Noll,
Action of micrococcal nuclease on chromatin and the location of histone H1.
1977,
Pubmed
Noll,
Internal structure of the chromatin subunit.
1974,
Pubmed
Osheroff,
DNA topoisomerase II from Drosophila melanogaster. Relaxation of supercoiled DNA.
1983,
Pubmed
Osheroff,
Eukaryotic topoisomerase II. Characterization of enzyme turnover.
1986,
Pubmed
Prunell,
Periodicity of deoxyribonuclease I digestion of chromatin.
1979,
Pubmed
Razvi,
A simple procedure for parallel sequence analysis of both strands of 5'-labeled DNA.
1983,
Pubmed
,
Xenbase
Ruberti,
Mechanism of chromatin assembly in Xenopus oocytes.
1986,
Pubmed
,
Xenbase
Ryoji,
Chromatin assembly in Xenopus oocytes: in vivo studies.
1984,
Pubmed
,
Xenbase
Sahyoun,
Protein kinase C phosphorylates topoisomerase II: topoisomerase activation and its possible role in phorbol ester-induced differentiation of HL-60 cells.
1986,
Pubmed
Sealy,
Novobiocin inhibits passive chromatin assembly in vitro.
1986,
Pubmed
,
Xenbase
Sinden,
Torsional tension in the DNA double helix measured with trimethylpsoralen in living E. coli cells: analogous measurements in insect and human cells.
1980,
Pubmed
Sollner-Webb,
A comparison of the digestion of nuclei and chromatin by staphylococcal nuclease.
1975,
Pubmed
Uemura,
Isolation of type I and II DNA topoisomerase mutants from fission yeast: single and double mutants show different phenotypes in cell growth and chromatin organization.
1984,
Pubmed
Wang,
DNA topoisomerases.
1985,
Pubmed
Weintraub,
Dissection of chromosome structure with trypsin and nucleases.
1974,
Pubmed
Weisbrod,
Active chromatin.
1982,
Pubmed
