Click
here to close Hello! We notice that
you are using Internet Explorer, which is not supported by Echinobase
and may cause the site to display incorrectly. We suggest using a
current version of Chrome,
FireFox,
or Safari.
Chromatin fibers observed in situ in frozen hydrated sections. Native fiber diameter is not correlated with nucleosome repeat length.
Woodcock CL
.
???displayArticle.abstract???
Chromatin fibers have been observed and measured in frozen hydrated sections of three types of cell (chicken erythrocytes and sperm of Patiria miniata and Thyone briareus) representing an approximately 20-bp range of nucleosomal repeat lengths. For sperm of the starfish P. miniata, it was possible to obtain images of chromatin fibers from cells that were swimming in seawater up to the moment of cryo-immobilization, thus providing a record of the native morphology of the chromatin of these cells. Glutaraldehyde fixation produced no significant changes in the ultrastructure or diameter of chromatin fibers, and fiber diameters observed in cryosections were similar to those recorded after low temperature embedding in Lowicryl K11M. Chromatin fiber diameters measured from cryosections of the three types of nuclei were similar, a striking contrast to the situation for chromatin isolated from these cell types, where a strong positive correlation between diameter and nucleosomal repeat length has been established. The demonstration of chromatin fibers in unfixed whole cells establishes an unequivocal baseline for the study of native chromatin and chromosome architecture. The significant differences between chromatin fibers in nucleo and after isolation supports a previous observation (P. J. Giannasca, R. A. Horowitz, and C. L. Woodcock. 1993. J. Cell Sci. 105:551-561), and suggests that structural studies on isolated material should be interpreted with caution until the changes that accompany chromatin isolation are understood.
Alegre,
The diameter of chromatin fibres depends on linker length.
1989, Pubmed,
Echinobase
Alegre,
The diameter of chromatin fibres depends on linker length.
1989,
Pubmed
,
Echinobase
Athey,
The diameters of frozen-hydrated chromatin fibers increase with DNA linker length: evidence in support of variable diameter models for chromatin.
1990,
Pubmed
,
Echinobase
Bordas,
The superstructure of chromatin and its condensation mechanism. II. Theoretical analysis of the X-ray scattering patterns and model calculations.
1986,
Pubmed
Davies,
Electron-microscope observations on the organization of the nucleus in chicken erythrocytes and a superunit thread hypothesis for chromosome structure.
1974,
Pubmed
Dubochet,
Cryo-electron microscopy of vitrified specimens.
1988,
Pubmed
Giannasca,
Transitions between in situ and isolated chromatin.
1993,
Pubmed
,
Echinobase
Horowitz,
Ultrastructural preservation of nuclei and chromatin: improvement with low-temperature methods.
1990,
Pubmed
Horowitz,
The three-dimensional architecture of chromatin in situ: electron tomography reveals fibers composed of a continuously variable zig-zag nucleosomal ribbon.
1994,
Pubmed
,
Echinobase
Horowitz,
Alternative staining methods for Lowicryl sections.
1992,
Pubmed
,
Echinobase
Kirschner,
Characterization of the nuclear envelope, pore complexes, and dense lamina of mouse liver nuclei by high resolution scanning electron microscopy.
1977,
Pubmed
Langmore,
Low angle x-ray diffraction studies of chromatin structure in vivo and in isolated nuclei and metaphase chromosomes.
1983,
Pubmed
,
Echinobase
McDowall,
Cryo-electron microscopy of vitrified chromosomes in situ.
1986,
Pubmed
Murray,
Electron microscopy of frozen hydrated eukaryotic flagella.
1986,
Pubmed
,
Echinobase
Poccia,
Transitions in histone variants during sea urchin spermatogenesis.
1987,
Pubmed
,
Echinobase
Rattner,
Higher order structure in metaphase chromosomes. II. The relationship between the 250 A fiber, superbeads and beads-on-a-string.
1978,
Pubmed
Ruiz-Carrillo,
Stability and reversibility of higher ordered structure of interphase chromatin: continuity of deoxyribonucleic acid is not required for maintenance of folded structure.
1980,
Pubmed
Stewart,
Transmission electron microscopy of frozen hydrated biological material.
1989,
Pubmed
Thoma,
Involvement of histone H1 in the organization of the nucleosome and of the salt-dependent superstructures of chromatin.
1979,
Pubmed
Tilney,
The polymerization of actin. II. How nonfilamentous actin becomes nonrandomly distributed in sperm: evidence for the association of this actin with membranes.
1976,
Pubmed
Ward,
Seasonal changes in testicular structure and localization of a sperm surface glycoprotein during spermatogenesis in sea urchins.
1993,
Pubmed
,
Echinobase
Williams,
Chromatin fibers are left-handed double helices with diameter and mass per unit length that depend on linker length.
1986,
Pubmed
,
Echinobase
Woodcock,
The higher-order structure of chromatin: evidence for a helical ribbon arrangement.
1984,
Pubmed
Woodcock,
Nucleus-associated intermediate filaments from chicken erythrocytes.
1980,
Pubmed
Woodcock,
A chromatin folding model that incorporates linker variability generates fibers resembling the native structures.
1993,
Pubmed
,
Echinobase
Zentgraf,
Differences of supranucleosomal organization in different kinds of chromatin: cell type-specific globular subunits containing different numbers of nucleosomes.
1984,
Pubmed
,
Echinobase
