The effect of histone H1 on the compaction of oligonucleosomes A quasielastic light scaitering study

Marion, Christian; Hesse-Bezot, C.; Bezot, P.; Marion, Marie‐Jeanne; Roux, B.; Bernengo, Jean‐Claude

doi:10.1016/0301-4622(85)80025-9

Cited by 11 publications

(5 citation statements)

References 62 publications

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“…3) Our measurements of DT also correlate with the micrographs in showing much less compaction for chicken chromatin depleted of histones H1 and H5. We obtain similar values ofDT using two methods for removing the H1 and H5, and our data are in agreement with a previous study (18).…”

Section: Discussionsupporting

confidence: 82%

Higher-order structure of Saccharomyces cerevisiae chromatin.

Lowary

Widom

1989

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

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We have developed a method for partially purifying chromatin from Saccharomyces cerevisiae (baker's yeast) to a level suitable for studies of its higher-order folding. This has required the use of yeast strains that are free of the ubiquitous yeast "killer" virus. Results from dynamic light scattering, electron microscopy, and x-ray diffraction show that the yeast chromatin undergoes a cation-dependent folding into 30-nm filaments that resemble those characteristic of higher-cell chromatin; moreover, the packing of nucleosomes within the yeast 30-nm filaments is similar to that of higher cells. These results imply that yeast has a protein or protein domain that serves the role of the histone H1 found in higher cells; physical and genetic studies of the yeast activity could help elucidate the structure and function of Hi. Images of the yeast 30-nm filaments can be used to test crossed-linker models for 30-nm filament structure.We are interested in using the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe as model organisms in studies of eukaryotic chromatin structure, principally for two reasons. (i) We would like to use yeast genetics to identify and study the proteins necessary for the highest levels of chromosome folding. (ii) Although the manner in which nucleosomes are packaged together in 30-nm chromatin filaments is known approximately, the connectivity of the structure is not known (1). S. cerevisiae and neuronal cells have approximately no linker DNA (2-4), so studies of the higher-order folding of such chromatin could place strong constraints on possible connectivities. Previous studies of neuronal chromatin have shown it to fold into a higher-order structure that appears similar to the 30-nm filaments of higher cells (3, 4). One would like to extend these results by using methods such as electron microscopy of negatively stained samples or x-ray diffraction to study the packing of nucleosomes within the neuronal chromatin 30-nm filaments. However, because it has not been possible to isolate long oligomers of this neuronal chromatin, no such studies have been carried out. One might hope that yeast chromatin would present no such difficulty.One must first address the question: are the folded states of yeast chromatin similar to those of higher cells? The sequences of the four core histones (particularly H3 and H4) of both yeasts are quite homologous to those of higher eukaryotes (5), and nuclease digestion experiments reveal a similar pattern of DNA protection except for subtle differences near the ends of the nucleosomal DNA (6). In the absence offurther information it is reasonable to suppose that yeast nucleosomes will be similar in size and shape to those of higher cells. Surprisingly, it is not known whether this similarity extends to higher levels of chromosome structure. One study reported electron microscopic evidence for the existence of a 30-nm filament-like state of S. cerevisiae chromatin (7), but this has remained a matter of debate (8). A protein homologous to higher-c...

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Section: Discussionsupporting

confidence: 82%

Higher-order structure of Saccharomyces cerevisiae chromatin.

Lowary

Widom

1989

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

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“…Such a characteristic was already reported for yeast chromatin [38]. The discrepancy of this result with previous works on animal chromatin [14,39,40] may suggest a less constrained structure for barley nucleosomes with regard to the animal counterparts. Nevertheless, a more precise quantification of H1 and of the protein-free linker DNA would be required to draw structural conclusions [41].…”

Section: Tionution Of Solublp Burley Chromatincontrasting

confidence: 56%

“…Approximate sedimentation coefficients could be calculated using the Fritsch's equation [35] for isokinetic gradients and are reported in Table 1 . Thus, the 'middle' fraction was chosen assuming a centrals value of 26 S, and an amplitude of 1 S. This value corresponds to rat liver hexanucleosomes, which seem to play an important role in the nucleosomal fiber [13,14]. In the same way, the 'bottom' fraction was chosen assuming an s value higher than 29 S. It is interesting to note that the s values of barley dimer and trimer were lower than (Fig.…”

Section: Tionution Of Solublp Burley Chromatinmentioning

confidence: 99%

Chromatin structure in barley nuclei

Mithieux

Roux

1983

European Journal of Biochemistry

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In order to study the chromatin structure of a higher plant we used a high-yield method, which allows one to obtain up to 1 O9 nuclei/kg fresh barley leaves. Significant amounts of low-ionic-strength-soluble chromatin can be extracted from these nuclei. Physicochemical properties wcre examined and discussed. Electric birefringence allowed us to observe the same transition in electro-optical properties as has been observed for animal chromatin, and suggested the existence of a symetrical structure occurring for approximately six nucleosomes. Circular dichroism showed that barley oligonucleosomes exhibit a higher molar ellipticity at 282 nm than total soluble chromatin and than their animal counterparts.It has been demonstrated that eukaryotic chromatin yields a repetitive nucleoprotein substructure for all organisms studied up to now (for reviews, see [I -31) Contrary to animal and fungal chromatin, very little is known concerning plant chromatin. Nuclcosomal DNA lengths of about 195 base pairs have been reported for rye embryos [IS], barley and tobacco [19], while shorter lengths were determined for pea-bud chromatin : 185 base pairs [20] and whole pea seedling chromatin: 170 base pairs [21].Barley (Horderum vulgaris) chromatin was chosen for two reasons. It presents in situ a highly condensed structure and it exhibits a high variability in histone H I and H2 composition, as do all gramineaes [22 -261. In this paper we present a technique allowing the isolation of large amounts of purified nuclei, and the recovery of a lowionic-strength-soluble chromatin. Physicochemical and electro-optical properties of this chromatin were examined, particularly circular dichroism and electric birefringence.

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“…dynamic light scattering. 22 The data prove that the isolated chromatin fragments exist in solution as dispersed particles, and measured quantities are not biased by non-specific aggregation, which is an important prerequisite for evaluation of the FCS amplitudes.…”

Section: Fcs: H2b-tagged Nucleosome Chains Diffuse Freely In Solutionmentioning

confidence: 95%