Chicken erythrocyte nucleus contains two classes of chromatin that differ in micrococcal nuclease susceptibility and solubility at physiological ionic strength.

Autor:	Fulmer AW, Bloomfield VA
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 1981 Oct; Vol. 78 (10), pp. 5968-72.
DOI:	10.1073/pnas.78.10.5968
Abstrakt:	Inactive chromatin of the chicken erythrocyte nucleus is shown to consist of two distinct classes (I and S). I chromatin (approximately 60% of the total genome) is insoluble at greater than 0.1 M ionic strength whereas S chromatin (approximately 40% of the total genome) is soluble at all ionic strengths studied (0.01--0.3 M). These chromatins are released from nuclei upon digestion with micrococcal nuclease by two separate parallel processes that do not have a precursor--product relationship to each other. Isolated I-chromatin fragments show a progressive reduction in size from 250 to approximately 50 nucleosome equivalents with increasing digestion times at 0-2 degrees C. Prolonged digestion of nuclei at 37 degrees C results in conversion of I chromatin to mononucleosomes that are insoluble at greater than 30 mM NaCl. Isolated S-chromatin fragments show a constant size distribution, independent of digestion time, that peaks at approximately 35 nucleosome equivalents. Prolonged digestion of nuclei at 37 degrees C results in the conversion of S chromatin to mononucleosomes that are soluble at physiological ionic strength. Both I and S chromatins contain a full complement of histones with no nonhistone proteins.
Databáze:	MEDLINE
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