Abstract
The morphology of metaphase chromosome-derived chromatin fibers released from cells by non-ionic detergent cell lysis in the presence of divalent cations has been studied by electron microscopy. In these preparations the euchromatic arms appear as a series of loops, 200–300 Å in diameter, which are composed of closely-apposed nucleosome arrays. The higher order fiber in chromosomes derived from detergent-lysed cells appears to be less stable than chromatin fibers obtained by mechanical cell lysis. The fiber breaks down into a series of non-uniform nucleosome aggregates (superbeads) and finally to chromatin in a beads-on-a-string morphology upon incubation at 31° for 20 min. These observations allow us to suggest a relationship between uniform thick fibers, superbead-containing fibers, and beads-on-a-string chromatin within metaphase chromosomes.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Brasch, K., Seligy, V.L., Setterfield, G.: Effects of low salt concentration on structural organization and template activity of chromatin in chicken erythrocyte nuclei. Exp. Cell Res. 65, 61–72 (1971)
Compton, J.L., Bellard, M., Chambone, P.: Biochemical evidence of variability in the DNA repeat length in chromatin of higher eukaryotes. Proc. nat. Acad. Sci. (Wash.) 73, 4382–4386 (1976)
Rattner, J.B., Hamkalo, B.A.: Higher order structure of metaphase chromosomes. I. The 250 Å fiber. Chromosoma (Berl.) 69, 363–372 (1978)
Wolfe, S.L.: The relationship of isolated chromosome fibers to the fibers of the embedded nucleolus. In: The biological basis of medicine (E. E. Ritlar, ed.), pp. 3–42. (1969)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Rattner, J.B., Hamkalo, B.A. Higher order structure in metaphase chromosomes. Chromosoma 69, 373–379 (1978). https://doi.org/10.1007/BF00332140
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00332140