Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.31.1 (micrococcal nuclease)
 2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Purified 15 S globin mRNA-protein (mRNP) complexes obtained by EDTA dissociation of duck reticulocytes polyribosomes were digested with the calcium dependant Staphylococcus aureus nuclease (EC 3. 1. 4. 7.). 25% of the globin mRNA sequences were resistant to extensive nuclease digestion as determined by TCA precipitation of the digested 15 S particles labelled in vivo with tritiated uridine. Polyacrylamide gel electrophoresis of the RNA from nuclease digested 15 S particles showed that the protected oligoribonucleotides were distributed into two distinct size classes of 25,000 and 12,000 MW. Comparison between in vitro iodine-labelled 9 S globin mRNA extracted from Staphylococcal nuclease digested 15 S mRNP particles was carried out by fingerprinting. Mapping of T1 ribonuclease digests by high-voltage electrophoresis and homochromatography showed that specific oligoribonucleotides were protected against nuclease attack by proteins of the 15 S mRNP.
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PMID:Evidence for the protection of specific RNA sequences in globin messenger ribonucleoprotein particles. 11 Dec 30

We have recently shown that, after the histones and most of the nonhistone proteins are gently removed from HeLa metaphase chromosomes, the chromosomal DNA is still highly organized and relatively compact. The structure of these histone-depleted chromosomes is due to the presence of a number of nonhistone proteins that form a central scaffold that retains the approximate size and shape of intact chromosomes and to which the DNA is attached, predominantly forming loops. We now demonstrate that the protein scaffold may be isolated independently of the DNA by treating HeLa chromosomes with micrococcal nuclease before removing the histones.The chromosomal scaffolds may be isolated by sucrose density gradient centrifugation as a well-defined peak that is stable in 2 M sodium chloride, but is dissociated by treatment with proteases, 4 M urea, or 0.1% sodium dodecyl sulfate. Polyacrylamide gel electrophoresis reveals that the protein content of scaffold preparations is identical to that of histone-depleted chromosomes. Fluorescence microscopy of purified scaffolds in isolation buffer shows that the particles still possess the familiar chromosome morphology. When the scaffolds are examined in the electron microscope, a fibrous structure with the approximate size and shape of intact, paired chromatids is seen. Less than 0.1% of the chromosomal DNA and virtually no histones are associated with the purified scaffold structures.
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PMID:Isolation of a protein scaffold from mitotic HeLa cell chromosomes. 27 Jul 27

Chromatin from Friend leukemia cells labeled with [14C]thymidine for 24 hr followed by [3H]thymidine for 10 min is converted into nucleosomes by staphylococcal nuclease at only half the rate that total chromatin is converted. Polyacrylamide gel electrophoresis of nucleosomal DNA from cells labeled for 24 hr with [14C]thymidine followed by 10 min with [3H]thymidine demonstrates that the internucleosomal spacer of newly replicated chromatin is approximately 20 base pairs shorter than that of total chromatin. The implications of this difference for models of chromatin structure are discussed.
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PMID:Altered nucleosome spacing in newly replicated chromatin from Friend leukemia cells. 28 12

The sensitivity of nuclei to micrococcal nuclease was compared in thyroid tissue obtained from euthyroid patients with solitary cold nodules and from patients with Graves' disease. A significant increase in the solubility and/or the sensitivity of nuclei to the nuclease was found in thyroid tissue from patients with Graves' disease. Electrophoretic analysis of DNA in chromatin solubilized by the nuclease revealed that the amount of oligonucleosomal DNA was increased, and that of polynucleosomal DNA was even more increased, in nuclei from Graves' thyroids than in those from normal thyroids. Polyacrylamide gel electrophoretic analysis in Triton acid-urea showed that the extent of histone acetylation in nuclei from Graves' thyroids was almost the same as in those from normal thyroids. These findings suggest that the state of chromatin organization in Graves' thyroid nuclei is different from that in normal thyroid nuclei and is independent of the extent of histone acetylation.
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PMID:Increased micrococcal nuclease sensitivity and/or solubility in nuclei from Graves' disease thyroid tissue. 654 27

Chromatin fragments of the RNA polymerase II-transcriptional complex were purified from the micrococcal nuclease digest of rat liver nuclei in the presence of n-butyrate, a potent histone deacetylase inhibitor. Polyacrylamide gel electrophoretic analysis in Triton acid-urea revealed that the extent of histone acetylation of the complex did not differ markedly from that of the total chromatin.
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PMID:Transcribing chromatin is not preferentially enriched with acetylated histones. 687 81

We have isolated a crude nuclear preparation from the unicellular red alga Porphyridium aerugineum and investigated the structure of Porphyridium chromatin. Electrophoresis of deproteinized DNA fragments produced by micrococcal nuclease digestion of Porphyridium nuclei gives a typical ladder pattern, indicative of a repeating structure. The DNA repeat-length, calculated from plots of multimer length against multimer number, varies somewhat between different digestions, ranging from 160 to 180 base-pairs (average 173). We interpret this as evidence of heterogeneity in repeat-length; the calculated repeat-length depends on the extent of digestion because chromatin sub-populations with longer repeat-lengths are on average digested earlier. Polyacrylamide/sodium dodecyl sulphate gel electrophoresis of basic proteins purified from Porphyridium nuclear preparations gives a pattern characteristic of core histones. Although our interpretation is complicated by some degradation, the result strongly suggests that Porphyridium chromatin contains each of the four core histones and that they are similar to those of higher eukaryotes. This, together with the micrococcal nuclease digestion results, demonstrates that Porphyridium chromatin is not fundamentally different from that of higher eukaryotes.
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PMID:Chromatin from the unicellular red alga Porphyridium has a nucleosome structure. 715 58