Studies on the mode of segregation of histone nu bodies during replication in HeLa cells

Seale, Ronald L.

doi:10.1016/0092-8674(76)90087-8

Cited by 128 publications

(80 citation statements)

References 18 publications

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“…However, newly synthesized and parental chromatins exhibit comparable micrococal nuclease digestion kinetics, indicating that newly synthesized chromatin contains full nucleosomes at regular spacing intervals [18]. Sedimentation studies with heavy isotope-labeled histones indicated that histone octamers segregate in a conserved manner [19].…”

Section: Introductionmentioning

confidence: 99%

Epigenetic inheritance: Uncontested?

Reinberg

2011

Cell Res

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"Epigenetics" is currently defined as "the inheritance of variation (-genetics) above and beyond (epi-) changes in the DNA sequence". Despite the fact that histones are believed to carry important epigenetic information, little is known about the molecular mechanisms of the inheritance of histone-based epigenetic information, including histone modifications and histone variants. Here we review recent progress and discuss potential models for the mitotic inheritance of histone modifications-based epigenetic information.

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Section: Introductionmentioning

confidence: 99%

Epigenetic inheritance: Uncontested?

Reinberg

2011

Cell Res

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“…Consequently it may be asked whether the same DNA polymerase's) extends both the all DNA chain on the continuous arm and the RNA-DNA hybrid chain on the discontinuous arm (16). Similarly, in the conservative model of chromatin replication, in which only one of the daughter chromosomes becomes associated with the parental histones (17,18), the continuous arm may be the more probable candidate for retaining the parental nucleosome structure because its doublestrandedness is least perturbed.…”

Section: Dna-dna Hybridizationmentioning

confidence: 99%

Okazaki pieces grow opposite to the replication fork direction during simian virus 40 DNA replication

1978

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Simian virus 40 replicating DNA was pulse labeled with a-32P-dATP using an acellular DNA replication system. Nascent DNA chains of less than 200 nucleotides (Okazaki pieces) were then isolated from the denatured replicating DNA by electrosieving through a polyacrylamide gel column. The purified Okazaki pieces were hybridized to separated strands of Bgl +Hpa simian virus 40 DNA restriction fragments immobilized on nitrocellulose filters. Only strands with polarity of the DNA replication fork direction hybridized with Okazaki pieces. Hence, Okazaki pieces in simian virus 40 are synthesized against the DNA replication fork direction.

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“…However, it has also been shown that newly replicated chromatin is relatively more susceptible to the action of micrococcal nuclease (11).…”

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confidence: 99%

Nucleosome periodicity in HeLa cell chromatin as probed by micrococcal nuclease.

Butt¹,

Jump²,

Smulson³

1979

Proc. Natl. Acad. Sci. U.S.A.

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When HeLa cell nuclei were treated with micrococcal nuclease (nucleate 3-oligonucleotidohydrolase, EC 3.1.4.7), lysed, and centrifuged, the supernatant from early digests contained two predominant classes of polynucleosomes of repeat size 8N and 16N. With increasing digestion time, the 16N polynucleosome appeared to be cleaved to the 8N species and finally to the basic subunit of chromatin. The size of the polynucleosomes has been determined by DNA analysis and on polyacrylamide electrophoretic gels of native chromatin particles. Thel6Npolynucleosome appears to be a unique higher ordered structural component of HeLa cell chromatin. Our recent report, showing that the nuclear protein-modifying enzyme poly(ADP-ribose) polymerase increases in specific activity progressively with increasing nucleosome repeat size up to 8-1ON, has been extended in the present study. Activity was also elevated in the polynucleosomes of the 16N structure preferentially cleaved by micrococcal nuclease, although specific activity of the enzyme was highest in octanucleosomes. Acceptors for poly(ADP-ribose) have also been determined in these particles.Despite recent advancement in our understanding of the structure of the nucleosome core particle, similar information concerning the higher order structure of chromatin remains largely undetermined (1)(2)(3). At low ionic strength the nucleofilament with diameter of 100 A is a single chain of nucleosomes (4-7). In the presence of monovalent and divalent cations, the diameter of the nucleofilament is increased to 250400 A (4, 5, 7). Based on electron micrographic data, Finch and Klug (4) postulated a solenoid model of chromatin.Kinetic studies performed on the action of micrococcal nuclease (nucleate 3'-oligonucleotidohydrolase, EC 3.1.4.7) on interphase chromatin and metaphase chromosomes (8-10) have supported the theory of random cleavage by the enzyme at uniformly susceptible sites on linker regions of polynucleosomes. However, it has also been shown that newly replicated chromatin is relatively more susceptible to the action of micrococcal nuclease (11).Using electron microscopic studies and sedimentation analysis on the chromatin produced after the digestion of lymphocyte nuclei by micrococcal nuclease, Hozier et al. (7) have postulated that chromatin is organized into superbeads containing six to ten nucleosomes. However, ambiguity about these structures still remains since Hozier et al. (7) were unable to isolate and resolve them on sucrose gradients. In kinetic studies performed in the work below, it has clearly been shown that micrococcal nuclease cleaves HeLa chromatin at a periodicity of eight nucleosomes. In addition to sedimentation analysis, we have been able to characterize these structures by (i) native chromatin gels, (ai) determination of the size of the DNA, and (Mi) the presence of a full complement of nuclear histones.These observations on nucleosome periodicity stemmed directly from our previous observation that the specific activity of a chromatin-bound enzyme, ...

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Studies on the mode of segregation of histone nu bodies during replication in HeLa cells

Cited by 128 publications

References 18 publications

Epigenetic inheritance: Uncontested?

Epigenetic inheritance: Uncontested?

Okazaki pieces grow opposite to the replication fork direction during simian virus 40 DNA replication

Nucleosome periodicity in HeLa cell chromatin as probed by micrococcal nuclease.

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