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

Digestion of chromatin with micrococcal nuclease under mild conditions results in the release of a minor chromatin fraction showing an increased RNA and non-histone protein content, a fast turnover of the non-histone proteins and the presence of rapidly labelled heterogeneous nuclear RNA (hnRNA) with half-life of about 20 min. Further digestion of the chromatin leads to the elimination of about 19% of the initial chromosomal DNA, thus leaving a second chromatin fraction relatively resistant to nuclease attack. This fraction has a low protein and RNA content and contains only metabolically stable non-histone proteins. No differences in the histone complement of the two fractions was found except for a 40% deficiency of H1 in the minor fraction.
 ...
PMID:Two chromatin fractions with different metabolic properties of non-histone proteins and of newly synthesized RNA. 28 97

Mononucleosomes (MN1) enriched in structural non-histone proteins and transcribed DNA sequences were obtained by limited digestion of trout testis nuclei with micrococcal nuclease followed by selective solubilization in 0.1 M NaCl. These monosomes consist of the four inner histones plus stoichiometric amounts of the non-histone protein H6, of the HMG group, complexed with 140 base pairs of DNA. Hybridization experiments indicate that MN1 DNA is enriched in sequences complementary to cytoplasmic polyadenylated RNA.
 ...
PMID:Partial purification of transcriptionally active nucleosomes from trout testis cells. 56 93

Mononucleosomes greatly enriched in non-histone proteins were prepared by limited digestion of testis nuclei with micrococcal nuclease. Five to fifteen per cent of the chromatin was solubilized and could be separated by adjustment to 0.1 M NaCl, into a soluble fraction MN1, consisting of mononucleosomes containing the four inner histones and the small basic non-histone, H6, associated with a 140-base-pair DNA fragment. H1 was notably absent in MN1. The fraction insoluble in 0.1 M NaCl (MN2) comprised a mixture of mono-, di-, tri-, and oligosomes. MN2 monosome fraction contained the four inner histones plus H1 and lacked H6 and the length of its DNA was 170 base-pairs. Previous work had shown that limited micrococcal nuclease digestion of trout testis nuclei released a great proportion of the non-histone protein, high mobility group protein T (HMG-T). It seems likely that HMG-T is the major non-histone protein located in the linker regions of a subset of nucleosomes containing the non-histone protein H6 as a major structural component. Moreover, the presence of HMG-T renders this subset of nucleosomes very sensitive to micrococcal nuclease. Hybridization experiments were performed to demonstrate that the DNA from MN1 monosomes corresponds to a subset of the trout testis genome. This DNA subset is greatly enriched in sequences that are present in cytoplasmic RNA. Chromatin subunits enriched in their content of H6 and HMG-T could also be obtained by limited digestion of trout testis chromatin with DNase II followed by precipitation with MgCl2.
 ...
PMID:A subset of trout testis nucleosomes enriched in transcribed DNA sequences contains high mobility group proteins as major structural components. 76 85

We performed a high resolution analysis of the chromatin structure within the regions required for distal transcription of the Drosophila melanogaster alcohol dehydrogenase gene (Adh). Using dimethyl sulfate, DNase I, and micrococcal nuclease as structural probes, and comparing chromatin structure in tissues isolated from several developmental stages, we have identified several sites of stage- and tissue-specific DNA-protein interactions that correlate with distal transcription initiation. Most were within previously identified cis-acting elements and/or in vitro protein binding sites of the adult enhancer (AAE) and distal promoter, including the TATA box. We also detected a novel stage-specific DNA-protein interaction at the Adf-2a binding site where a non-histone protein was bound to the DNA on the surface of a positioned nucleosome previously identified between the distal promoter and adult enhancer. In addition to footprints, we have also revealed stage- and tissue-specific DNA helix deformations between many of the non-histone protein binding sites. These helix distortions suggest there are interactions among the adjacently bound proteins that result in bending or kinking of the intervening DNA. The distal promoter and AAE have an accessible chromatin conformation in fat body prior to the third larval instar and many of the regulatory proteins that bind in these regions are also available before distal transcription begins. Nevertheless, the timing of DNA-protein interactions in the distal promoter and AAE suggest these proteins do not bind individually or assemble progressively as they and their binding sites become available. Instead, there appears to be a coordinated assembly of a large cooperative complex of proteins interacting with the distal promoter, the positioned nucleosome, the enhancer of the distal promoter (the AAE), and each other.
 ...
PMID:In vivo stage- and tissue-specific DNA-protein interactions at the D. melanogaster alcohol dehydrogenase distal promoter and adult enhancer. 143 59

We present evidence that T3 can alter the ADP-ribosylation of chromatin associated proteins. Nuclei from GH1 cells were incubated with [adenylate-32P]NAD and the radioactivity incorporated into histone and non-histone proteins was quantitated and analyzed by gel electrophoresis and autoradiography. Incubation of GH1 cells for 24 h with T3 lowered by 40-70% the [32P]ADP-ribose incorporated into nuclear proteins. However, incubation for 3 h with T3 resulted in a stimulation instead of a decrease of in vitro [32P]ADP-ribose incorporation. The major ADP-ribosylated component electrophoresed as a 120,000 molecular mass non-histone protein, and radiolabeled histones were also observed. The same protein species were observed for all the experimental groups and T3 affected the extent of ADP-ribosylation but did not alter the sedimentation of the [32P]ADP-ribosylated components excised from chromatin after micrococcal nuclease digestion.
 ...
PMID:Influence of thyroid hormone on ADP-ribosylation of nuclear proteins in cultured GH1 cells. 200 28

The organization of chromatin in D. melanogaster ribosomal repeats with and without insertions was studied. We have shown earlier that upon digestion with micrococcal nuclease a "non-transcribed" intergenic spacer produces unusual chromatin particles containing DNA fragments 200-280 b.p. in length. These particles sediment like H1-containing nucleosomes, are stable only in the presence of polyamines, and are probably bound to some non-histone protein. The content of core histones and H1 in different regions of ribosomal genes has been studied by two-dimensional electrophoresis of chromatin particles and by "protein-image" hybridization. The content of histones and respectively the degree of chromatin condensation increase in the following order: the 1kb-long region surrounding the initiation site is practically free of histones less than the region of 240 b.p. repeats from the intergenic spacer, containing homologies with the ribosomal promotor less than coding region preceding the usual site of insertions less than coding region lying behind this site less than inactive type II ribosomal insertion. Therefore, the region of the beginning of transcription of most ribosomal genes is in an active conformation, even though at least 75% of the genes are repressed. Ribosomal insertions are in a compact, repressed form. We suggest that their inhibitory action on the transcription of corresponding genes at the molecular level is similar to the position effect of heterochromatic regions at the chromosomal level.
 ...
PMID:[Gradient condensation of chromatin in ribosomal genes of Drosophila melanogaster]. 313 62

Non-histone protein fraction NHCP1 of micrococcal nuclease-sensitive and nuclease-resistant chromatin from Kirkman-Robbins hepatoma and hamster liver was studied by two-dimensional electrophoresis followed by Coomassie and silver staining and by microcomplement fixation technique in the presence of antibodies elicited against NHCP1 of both tissues. Apart from many common spots several tissue specific components associated with either nuclease-sensitive or nuclease-resistant chromatin were found. The presence of tissue specific components among NHCP1 from hepatoma and liver was confirmed by immunological analysis. It was stated that these components are exclusively localized in nuclease-resistant part of chromatin from neoplastic and normal tissues thus suggesting their structural function.
 ...
PMID:Molecular and functional diversity of non-histone protein fraction NHCP1 from hamster Kirkman-Robbins hepatoma and liver. 377 86

The binding of non-histone protein from mouse spleen chromatin located in the sites highly sensitive to micrococcal nuclease and DNA-ase I, to DNA and histones was studied. The binding of the DNA-protein complexes to nitrocellulose filters demonstrated the absence of protein binding to DNA. A highly selective binding of protein PS1 to histones H1 and H2A and to one of the non-histone proteins (presumably HMG 14) was revealed. It is concluded that protein PS1 is incorporated into chromatin by the protein-protein interactions.
 ...
PMID:[Interaction of the non-histone protein PS1 with some chromatin components]. 627 Dec 68

The trout testis contains two major high mobility group (HMG) proteins HMG-T and H6 which, although related to the four mammalian HMGs, exhibit distinct variation as evidenced by differences in electrophoretic mobility and amino acid sequence. Previous work using various endonucleases as probes has shown that HMG-T and H6 are located at specific sites in the testis chromatin. The differentiation of testis cells during spermatogenesis is characterized by a unique transition from a histone-packaged genome to one bound by a class of small molecular weight, highly basic proteins, the protamines. Questions arise as to whether any of the HMG variability may be unique to the process of spermatogenesis and whether the histone-protamine transition occurring in most testis cells affects the HMG protein distribution and/or the specificity of the probe. In an attempt to answer these questions, the distribution of the HMG proteins in the chromatin of trout liver, a tissue lacking protamine, has been studied and comparisons made with testis. Liver HMGs exhibit the same electrophoretic characteristics as the testis HMGs indicating that the variability when compared to mammalian HMGs is primarily phylogenetic in origin rather than tissue-specific. Furthermore, micrococcal nuclease digestion of liver nuclei and its effect on the subsequent HMG protein distribution during chromatin fractionation yields a pattern very similar to that for testis, suggesting that the interaction of the HMGs with the remaining testis nucleohistone is not significantly altered by the ongoing transition to nucleoprotamine. Finally, the HMGs represent an unusually high proportion of the total testis non-histone protein population; the implications of this are discussed.
 ...
PMID:Comparison of the high mobility group proteins and their chromatin distribution in trout testis and liver. 645 90

Mono- and dinucleosomes preferentially cleaved from mouse myeloma chromatin by very mild micrococcal nuclease digestion at 0 degree C are soluble and are released from nuclei under near-physiological conditions in which normal nucleosomes containing Hl are insoluble. These nucleosomes are highly enriched in RNA, high-mobility-group proteins and a unique subset of other non-histone proteins. They are nearly devoid of histone Hl and contain DNA significantly less methylated than whole myeloma DNA, indicating that they comprise a subset of genomic sequences. Previously we have shown that this fraction is enriched in transcribed DNA sequences. Non-histone proteins that co-sedimented with readily solubilized nucleosomes included many of the most basic, low-to-moderate molecular weight chromosomal proteins. Many of these proteins were also preferentially acetylated in vivo. The residual, pelleted chromatin was highly enriched in high molecular weight proteins (greater than 60 000), and very depleted in medium molecular weight proteins. Readily solubilized nucleoproteins sedimenting like mononucleosomes were partly resolved by electrophoresis, under non-denaturing conditions, into several subfractions differing significantly in non-histone protein contents. Methods described here should be useful for identifying and isolating non-histone proteins bound to nucleosomes and other chromatin regions that are structurally and functionally unique.
 ...
PMID:Non-histone proteins of soluble nucleoproteins released from mouse myeloma nuclei by mild micrococcal nuclease digestion. 672 66


1 2 3 Next >>