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PubMed · 954084

Chromatin structure visualization by immunoelectron microscopy.

M Bustin·D Goldblatt·R Sperling
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Abstract

Antibodies elicited in rabbits by chromatin and by purified histone H2B have been used to study the structure of chromatin by immunoelectron microscopy. Chromatin spread on grids reveals a structure of closely packed spherical particles with an average diameter of 104 A, arranged either in clusters or in linear arrays of beads, some of which have a supercoil-like arrangement. No DNA strings connecting the beads could be observed. Upon antibody binding, the diameter of the particles increases up to 300 A. This size is compatible with a model where one layer of gamma globulin molecules 110 A long encircles a sphere of chromatin 100 A in diameter. The presence of rabbit gamma globulins on the enlarged beads has been verified by the addition of ferritin-labeled goat anti-rabbit gamma globulins. Anti-chromatin sera which react with nonhistone proteins but not with free histones or DNA react with more than 95% of the beads; this suggests that most of the beads contain nonhistone proteins. Since the number of nonhistone proteins is large, it is improbable that each sphere contains a full complement of these proteins. We therefore suggest that the various chromatin spheres contain different types of nonhistone proteins. About 90% of the chromatin spheres reacted with antibodies to histone H2B, suggesting the most of the chromatin beads contain this type of histone.

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Antigen-Antibody ReactionsChromatinHistonesMicroscopy, ElectronModels, BiologicalNucleoproteinsJournal Article

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M Bustin, D Goldblatt, R Sperling. 1976. Chromatin structure visualization by immunoelectron microscopy.. https://doi.org/10.1016/0092-8674(76)90029-5

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