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Published February 1, 1978 | public
Journal Article Open

Chromatin Structure in the Cellular Slime Mold Dictyostelium discoideum

Abstract

The structure of Dictyostelium discoideum chromatin has been studied by the following techniques: electron microscopy, staphylococcal nuclease digestion, acrylamide gel electrophoresis, sucrose gradient centrifugation, and melting. The basic unit of chromatin is the nucleosome, which is a particle 98.6 angstrom in diameter. Approximately 50% of the chromatin is protected from nuclease digestion, but this decreases when protease activity is not inhibited. The nucleosome contains 187 base pairs of DNA, including a 137-base-pair core and a 50-base-pair linker. The monomer nucleosome has an s20,w value of 11.5 S on isokinetic sucrose gradients. When the chromatin is melted, four transitions are observed, at 54.5 degrees, 66.7 degrees, 74.9 degrees, and 79.7 degrees. The structure of Dictyostelium chromatin is very similar to that seen in higher eukaryotes.

Additional Information

Copyright © 1978 by the National Academy of Sciences. Contributed by James Bonner, November 14, 1977. We thank Dr. R.B. Wallace, T.D. Sargent, and J.W. Posakony for many valuable discussions. We also thank R.F. Murphy for the computer analysis of the data and Dr. Karyl Grohmann for the OX174 restriction fragments. This work was supported in part by U.S. Public Health Service Grant GM-13762, by U.S. Public Health Service Training Grant GM00082, and by a California Institute of Technology Fellowship to A.C.B. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

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August 22, 2023
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October 16, 2023