Nascent DNA in nucleosome-like structures from chromatin

Levy, Allan H.; Jakob, Karl M.

doi:10.1016/0092-8674(78)90112-5

Cited by 87 publications

(48 citation statements)

References 27 publications

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“…They probably exist also in Hl-depleted chromatin (M. Noll It is much easier to think of a possible physiological role of the closely spaced core particles. Their similarity to structures observed at the replication fork is striking (6). In both cases dinucleosomes of about 300 base pairs that are relatively resistant to cleavage by micrococcal nuclease are observed.…”

Section: Discussionmentioning

confidence: 61%

“…However, this type of reconstituted chromatin exhibits a considerably shorter DNA length per nucleosome (4). Such a reduced DNA size per nucleosome has been reported to exist transiently in newly replicated chromatin in vivo (6) and may occur also in other regions of native chromatin devoid of Hl. In this study, the self-assembly of DNA and the four histones of the nucleosome core is used to examine the possible arrangements of nucleosomes in such regions and to analyze the structure of the nucleosome core in greater detail.…”

Section: Introductionmentioning

confidence: 98%

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Self-assembly of single and closely spaced nucleosome core particles

et al. 1980

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Section: Discussionmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 98%

Self-assembly of single and closely spaced nucleosome core particles

et al. 1980

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“…Moreover, it was only the behavior of the newly synthesized Hi that was monitored, and, as already known, old histones also participate in the formation of newly replicated chromatin. Further studies using micrococcal nuclease digestion have reported that 2-5 min after DNA replication, the mononucleosomes in nascent chromatin are represented mostly by core particles (14,15,19,20,28). In another similar study some of the monomeric nucleosomes obtained from nascent chromatin within 30 sec after DNA synthesis contained histone Hi.…”

Section: Introductionmentioning

confidence: 88%

“…Nascent chromatin is highly sensitive to nonspecific nucleases (13-18). The newly made nucleosomes are unstable, and they easily slide along DNA during nuclease digestion (19), thereby forming closely packed core particles (20,21) and decreasing the size of the nucleosomal repeat (22). The histones themselves, especially the newly synthesized ones, are bound weakly to nascent DNA (e.g., refs.…”

mentioning

confidence: 99%

Histone H1 deposition and histone-DNA interactions in replicating chromatin.

Bavykin

Srebreva

Banchev

et al. 1993

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

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An immunochemical method for analyzing protein interactions with BrdUrd-substituted DNA was used to study binding of histones to nascent DNA in nuclei. The results indicate that in Ehrlich ascites tumor (EAT) cells, histone Hi deposits on newly replicated DNA simultaneously with or immediately after core histone deposition so that in chromatin replicated for 3 min, the stoichiometry of the histones is the same as in bulk chromatin. All histones, and especially histone Hi, interact with nascent DNA more weakly than with bulk chromatin, although the efficiency of interaction via the globular domains seems to be the same for both types of chromatin.Assembly of eukaryotic chromatin during the postreplication period is a complex, multi-step process (1-3). Apparently, each preexisting nucleosome dissociates into one H3/H4 tetramer and two H2A/H2B dimers, which recombine with newly synthesized histones and segregate randomly to either daughter DNA duplex (for an opposing opinion, see refs. 4-7). Additionally, new histones H3/H4 are deposited on the nascent DNA, while the majority of new H2A/H2B dimers are associated with nonreplicated DNA, and new Hi is randomly distributed over chromatin (1,8). Special protein complexes may target the sequential deposition of histones onto DNA, with histones H3 and H4 joining replicating DNA first, followed by addition of histones H2A and H2B (9-12). The structure of new chromatin during the first 10-20 min after DNA replication is distinguishable from that of bulk chromatin. Nascent chromatin is highly sensitive to nonspecific nucleases (13-18). The newly made nucleosomes are unstable, and they easily slide along DNA during nuclease digestion (19), thereby forming closely packed core particles (20,21) and decreasing the size of the nucleosomal repeat (22). The histones themselves, especially the newly synthesized ones, are bound weakly to nascent DNA (e.g., refs. 19 and 23).The higher order structure of newly replicated chromatin is probably unfolded (12,(24)(25)(26). Maturation of newly replicated chromatin is suggested to be mediated by histone Hi, which is known to play an important role in organization of the chromatosome and of the higher order structures of chromatin (27). However, it is not as yet clear when histone Hi is deposited during maturation. Earlier data obtained on fractionated chromatin were interpreted as indicating that nascent histone Hi appeared in chromatin only 10-20 min after DNA replication (12). As discussed by the authors themselves, however, the results could not unambiguously distinguish between random association to bulk chromatin as opposed to late association to nascent chromatin. Moreover, it was only the behavior of the newly synthesized Hi that was monitored, and, as already known, old histones also participate in the formation of newly replicated chromatin. Further studies using micrococcal nuclease digestion have reported that 2-5 min after DNA replication, the mononucleosomes in nascent chromatin are represented mostly by core particles ...

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“…The observations that the average spacing of nucleosomes changes during replication (6) and development (7)(8)(9)(10) and that the nucleosomal repeat disappears during transcription (11; Levy and Noll, submitted) imply that the nucleosomes cannot occupy a unique phase all the time. Early studies demonstrated that there is no single phase relation between nucleosomes and the bulk of the unique DNA sequences (12,13).…”

Section: Introductionmentioning

confidence: 99%