Histone H3 thiol reactivity and acetyltransferases in chicken erythrocyte nuclei.

摘要: Chicken erythrocyte nuclei previously incubated separately with two novel mercury compounds (N-chloromercuribenzoyl)-biocytin and bis(p-(chloromercuribenzoyl))-[3H]lysine diamide) were digested micrococcal nuclease the digest products fractionated according to their solubility in 0.15 M NaCl molecular size. The identity quantitation of chromatin fractions proteins containing covalently bound determined by Western blotting, autoradiography, scintillation counting. most highly acetylated species histone H3 NaCl-soluble polynucleosome fraction also contained highest proportion mercury. This contains hyperacetylated core histones, is depleted linker enriched nonhistone proteins. Histone mononucleosomes, which are unacetylated lack was 45% less labeled than fraction. In NaCl-insoluble polynucleosomes, contain histones molar proportions 63% labeled. Allowing for differential abundance these subfractions nucleus, relative reactivities 50, 7, 1 respectively. Thus a gradation exists correlates increasing hyperacetylation depletion. High mobility group 2, found subnucleosome particles fraction, extensively mercury-labeled. Distribution acetyltransferase activity among salt- size-resolved produced almost 5-fold greater supernatant pellet. Furthermore, activity, tightly undigested chromatin, rapidly released both DNase I. For short digestion times enzyme associated salt-soluble but at longer appears be free from intact nucleosomes. may localized globin domain erythrocytes maintains that region state results an altered binding reflected change reactivity usually inaccessible cysteine 110.