Structure and Function of Chromatin

Lilley, David M.J.; Pardon, J. F.

doi:10.1146/annurev.ge.13.120179.001213

Cited by 82 publications

(36 citation statements)

References 112 publications

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“…One possible concern, therefore, is the phenomenon of dilution-driven dissociation of nucleosomes. [40][41][42] While previous studies suggest that a fraction of nucleosomes may dissociate upon dilution, we do not believe this alters our conclusions or biases our measured force distributions.…”

Section: Potential Effect Of Dilutionmentioning

confidence: 61%

Forced Unraveling of Nucleosomes Assembled on Heterogeneous DNA Using Core Histones, NAP-1, and ACF

Gemmen

Sim

Haushalter

et al. 2005

Journal of Molecular Biology

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Section: Potential Effect Of Dilutionmentioning

confidence: 61%

Forced Unraveling of Nucleosomes Assembled on Heterogeneous DNA Using Core Histones, NAP-1, and ACF

Gemmen

Sim

Haushalter

et al. 2005

Journal of Molecular Biology

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“…Nucleases have been extensively used as structural probes to gain detailed information about the organization of DNA in the nucleosome core (for reviews see references [1][2][3][4]. DNase I has been used in particular in nucleosome digestion studies, and both the relative exposure of DNA sites (S, 6) as well as the precise location of those sites (7) have been determined.…”

Section: Introductionmentioning

confidence: 99%

DNase II digestion of the nucleosome core: precise locations and relative exposures of sites

Lutter

1981

Nucl Acids Res

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The precise locations and relative exposures of the DNase II-accessible sites in the nucleosome core DNA are determined using techniques previously employed for the enzyme DNase I. It is found that there are a nuber of similarities between the site exposure patterns for the two enzymes but that in general the DNase II seems to discriminate less among adjacent sites' accessibilities than does DNase I.The two enzymes attack essentially the same positions in the DNA, the average difference between the precise location of a site being less than one-half base for the two enzymes. Such close similarities in the digestion patterns of two enzymes with such different mechanisms of scission show that the patterns reflect the structure of the nucloosome core and not merely the properties of the particular enzyme used.

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“…The DNA linking the cores is not invariant; its average length varies with species, cell type, and developmental stage (8)(9)(10)(11)(12)(13)(14). The functional significance of this variability is unknown, although transcriptional activity, cell proliferation rate, and chromosome condensation are among the functions that could be affected by variations in spacer length (3,8). Also unclear is the underlying structural basis ofthis variability; different spacer lengths could arise from differences in Hi histones, core histones (especially H2A and H2B variants), posttranslational modifications, or nonhistone proteins (3).…”

mentioning

confidence: 99%

“…The functional significance of this variability is unknown, although transcriptional activity, cell proliferation rate, and chromosome condensation are among the functions that could be affected by variations in spacer length (3,8). Also unclear is the underlying structural basis ofthis variability; different spacer lengths could arise from differences in Hi histones, core histones (especially H2A and H2B variants), posttranslational modifications, or nonhistone proteins (3). Of these, the potential role of the very lysine-rich (Hl-like) histones has received the most attention; a number ofauthors have described correlations between alterations in nucleosome spacing and changes in the lysine-rich histone composition of the chromatin (10,11,15,16).…”

mentioning

confidence: 99%

Alterations in chromatin structure during early sea urchin embryogenesis.

Savić¹,

Richman²,

Williamson³

et al. 1981

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

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Sea urchin sperm before fertilization possess the longest nucleosome repeat length yet determined for any chromatin. By the time the fertilized egg gives rise to a blastula or gastrula embryo, the chromatin has a considerably shorter repeat length and, in addition, a sequence of different histone variants of HI, H2A, and H2B has appeared. We have investigated the relationship between these variations in histone composition and concomitant alterations in chromatin structure during the earliest stages of embryogenesis in two species of sea urchin. In contrast to the long repeat distance in sperm, chromatin loaded with cleavage-stage histones has a much smaller repeat. Later stages containing predominantly a histones display an intermediate spacing.More detailed analysis of the events in the first cell cycle was carried out with polyspermically fertilized eggs. During the first 30 min after fertilization, in which sperm-specific HI is completely replaced by cleavage-stage HI, the male pronuclear repeat remains unchanged. The decrease toward the repeat length ofcleavage stages begins at about the time of DNA synthesis. Higher degrees of polyspermy extend the length of the cell cycle, including the duration of S phase and the length of time to reach the first chromosome condensation. At these higher degrees of polyspermy, the decrease in repeat length is also slowed. We conclude that the adjustment of the arrangement of nucleosomes in embryonic chromatin from that found in sperm can occur within the first cell cycle and that its timing is cell-cycle dependent. The adjustment is separable from a corresponding change in HI composition. The structure ofeukaryote chromatin is based on repeating subunits, or nucleosomes, linked by structurally distinct regions of spacer DNA. Core nucleosomes invariably contain 146 base pairs (bp) of nuclease-resistant DNA organized by a protein octamer consisting of two each ofhistones H2A, H2B, H3, and H4 (1-4).Another class of histones, Hi, is not contained in the core structure and is probably associated with the spacer DNA linking the cores (5-7). The DNA linking the cores is not invariant; its average length varies with species, cell type, and developmental stage (8)(9)(10)(11)(12)(13)(14). The functional significance of this variability is unknown, although transcriptional activity, cell proliferation rate, and chromosome condensation are among the functions that could be affected by variations in spacer length (3,8). Also unclear is the underlying structural basis ofthis variability; different spacer lengths could arise from differences in Hi histones, core histones (especially H2A and H2B variants), posttranslational modifications, or nonhistone proteins (3). Of these, the potential role of the very lysine-rich (Hl-like) histones has received the most attention; a number ofauthors have described correlations between alterations in nucleosome spacing and changes in the lysine-rich histone composition of the chromatin (10,11,15,16).One potentially fruitful system in which t...

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Structure and Function of Chromatin

Cited by 82 publications

References 112 publications

Forced Unraveling of Nucleosomes Assembled on Heterogeneous DNA Using Core Histones, NAP-1, and ACF

Forced Unraveling of Nucleosomes Assembled on Heterogeneous DNA Using Core Histones, NAP-1, and ACF

DNase II digestion of the nucleosome core: precise locations and relative exposures of sites

Alterations in chromatin structure during early sea urchin embryogenesis.

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