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)

In vitro studies have demonstrated that the estrogen receptor (ER) can bind to the rat PRL estrogen response element (ERE) located 1700 basepairs upstream of the transcriptional start site. However, the mechanism by which the receptor-DNA complex influences the activity of RNA polymerase located in the promoter region is not understood. To begin investigating this process, we developed cell lines derived from GH3 cells that contain steroid-responsive bovine papillomavirus minichromosomes. Within these minichromosomes is a hybrid gene composed of the 5' flanking region of the PRL gene, driving the expression of the Tn5 gene. The episomal PRL DNA sequences responded to 17 beta-estradiol (E2) by increasing the rate of Tn5 gene transcription. Nucleosome mapping experiments using micrococcal nuclease demonstrated that nucleosome-like structures were assembled on the minichromosome in an ordered array separated by 150-200 basepairs of DNA. Novel S1 nuclease as well as DNase-I-hypersensitive sites in the chromatin of the promoter and distal regulatory regions of the episomal PRL gene were detected by indirect end-labeling studies. The nuclease hypersensitive sites in the distal region containing the ERE were modified after treatment of the cells with either E2 or the antiestrogen 4-hydroxytamoxifen. However, only E2 treatment of cells resulted in an increase in the nuclease hypersensitivity of the promoter region and induced gene expression, while antiestrogen treatment had no effect on either parameter. This suggests that complex interactions between factors located at the distal and proximal regulatory regions ultimately determine the transcriptional response of the PRL gene to E2.
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PMID:An interaction between the 5' flanking distal and proximal regulatory domains of the rat prolactin gene is required for transcriptional activation by estrogens. 196 74

A cell-free system for the study of transcription of African swine fever virus (ASFV) mRNA was developed from cytoplasmic extracts of infected cells permeabilized with lysolecithin. Extracts prepared from infected cells early and late after infection incorporated [alpha-32P]UTP into acid-insoluble material that was resistant to DNase and sensitive to RNase. The incorporation was inhibited by actinomycin D but not by alpha-amanitin. The presence of the nuclei was not required. In vitro transcription was optimal at pH 7.9 and at concentrations of 100 mM NH4Cl, 5 mM magnesium acetate, and 250 microM MnCl2. Early infected cell extracts transcribed from endogenous viral DNA a set of RNAs similar in electrophoretic migration to that observed in intact infected cells. Late infected cell extracts seemed to be unable to transcribe new RNA species besides those transcribed early after infection. The activity of the extracts could be made dependent on exogenous templates by digestion with micrococcal nuclease. RNAs transcribed after addition of native or denatured viral DNA to nuclease-treated extracts were indistinguishable from those transcribed from endogenous viral DNA. Late infected cell extracts digested with micrococcal nuclease were also active in transcribing virus-specific RNA from p2SB21, a recombinant plasmid containing the SalI B fragment of ASFV DNA.
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PMID:In vitro transcription by cytoplasmic extracts from cells infected with African swine fever virus. 259 35

Monoclonal antibodies (MAbs) against Staphylococcus aureus thermonuclease (TN) were raised by immunizing BALB/c mice with a commercial TN preparation. Six monoclones were generated producing MAbs specific for S. aureus TN as tested in Western blots and ELISA. They all combined with a 17 kD and a 21 kD protein, respectively, both of which showed DNase activity. All MAbs were of IgG1 isotype with kappa light chain. Competition ELISA showed that five of the MAbs recognized a total of three different binding sites of TN, designated I, II and III, respectively. Only the anti-site II MAbs inhibited the DNase activity. A MAb-based sandwich ELISA showed a lower detection limit for TN of approximately 0.5 ng/ml protein. Only S. aureus strains (culture supernatants) showed positive ELISA (31 positive/31 tested), although other tested gram positive cocci produced thermostable nucleases. The MAbs have potentials as reagents for rapid and specific detection of S. aureus.
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PMID:Generation and characterization of monoclonal antibodies against Staphylococcus aureus thermonuclease. 292 Jan 4

In this work we study the effects of an intercalating antitumoral agent: 9-hydroxy-2-methyl ellipticinium (NMHE) on the structure of chromatin, using micrococcal nuclease and DNase 1 as structural probes. The binding of the drug to chromatin, either in vitro or in the nuclei, induces two structural changes of chromatin: (a) an unfolding of the overall structure which results in an activation of the rate of degradation of chromatin by micrococcal nuclease and (b) a disorganisation of the core particle structure leading to the unwrapping of the DNA from the histone core. Moreover, by studying the interaction of MMHE with nuclei labeled in the active regions of the genome through a nick-translation reaction, it appears that the drug is overconcentrated in these regions and does not induce any new structural changes. The interaction of NMHE with DNase 1-sensitive regions of chromatin indicates that these regions are already "open" or relaxed and represent a preferential target for the drug.
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PMID:Interaction of an intercalating antitumoral agent: 9-hydroxy-2-methyl ellipticinium (NMHE) with chromatin. 367 13

With the use of a reconstituted poly(ADP-ribosyl)ating enzyme system and three purified nucleases, micrococcal nuclease (MN), bull seminal RNase (BS RNase) and Ca2+, Mg2+-dependent endonuclease (BS DNase), as model acceptor proteins for ADP-ribose, the effect of ionic strength on the modification reaction was examined in detail. When these three nucleases were extensively poly(ADP-ribosyl)ated in this system at a low ionic strength (5 mM Tris), they were all inhibited by about 80% and the chain length of the polymer covalently bound to the nucleases was 13 to 23 ADP-ribose units. The observed inhibition was markedly prevented by increasing the ionic strength in the reaction mixture with a concomitant decrease in the polymer size bound to the nucleases. The NaCl concentrations required for decreasing the extent of the inhibition to half of the maximum were calculated to be 20, 50, and 100 mM for MN, BS RNase, and BS DNase, respectively. These values are similar to the NaCl concentrations required for decreasing the average chain lengths of the polymer to half, suggesting that the length of polymer is closely correlated to the extent of inhibition of these nucleases. DNA-binding affinities of these nucleases, expressed in terms of the NaCl concentrations required for eluting the enzymes from DNA-cellulose, were 140, 280, and 340 mM for MN, BS RNase, and BS DNase, respectively. Considering that maintainance of a ternary complex of poly(ADP-ribose) synthetase, acceptor and DNA may be essential for the modification reaction, the relatively strong salt effect observed in the modification of MN may be explained by its low DNA-binding affinity.
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PMID:Effect of ionic strength on chain elongation in ADP-ribosylation of various nucleases. 371 Oct 53

The thermonuclease test for rapid identification of Staphylococcus aureus in blood cultures was evaluated by using 16 different blood culture media and 4 DNase agar media. The reliability of this test was profoundly medium dependent, and the source of the DNase agar was particularly important.
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PMID:Medium dependence for rapid detection of thermonuclease activity in blood culture broths. 376 Jan 43

Mouse L-cell nucleoli were isolated from sonicated nuclei by centrifugation and extensively treated with pancreatic DNase or micrococcal nuclease to obtain "core nucleoli." Core nucleoli still contained the precursors to rRNA and about 1% of the total nuclear DNA, which remained tightly bound even after the removal of some chromatin proteins with 2 M NaCl. The core nucleolar DNA electrophoresed in a series of discrete bands, 20 to about 200 base pairs in length. Hybridization tests with specific DNA probes showed that the DNA was devoid of sequences complementary to mouse satellite, mouse Alu-like, and 5S RNA sequences. It also lacked sequences coding for cytoplasmic rRNA species, since it did not hybridize to the 18S to 28S portion of rDNA in Northern blot analyses and none of it was protected by hybridization to a 100-fold excess of total cytoplasmic RNA in S1 nuclease assays. However, the core nucleolar DNA did hybridize to nontranscribed and external transcribed spacer rDNA sequences. We infer that specific portions of rDNA are protected from DNase action by a tight association with nucleolar structural proteins.
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PMID:Localization of specific rDNA spacer sequences to the mouse L-cell nucleolar matrix. 403 54

Exonucleolytic cleavage of DNA by the recBC DNase is accompained by a DNA-dependent ATP hydrolysis that ceases when the DNA that has been digested to a limit. On the other hand, DNA that has been crosslinked by 4,5',8-trimethylpsoralen in the presence of 360-nm light remains an effective cofactor in the ATPase reaction, but is resistant to digestion by the enzyme. Psoralentreated DNA is degraded by pancreatic DNase, micrococcal nuclease, and Escherichia coli B restriction enzyme, but not by Neurospora crassa nuclease, suggesting that crosslinking did not grossly distort the duplex structure of the DNA. The psoralen-DNA is not a potent inhibitor, but competes with single-stranded DNA from bacteriophage fd for the recBC DNase to roughly the same extent as does normal duplex DNA. DNA treated with psoralen in the dark, exposed to 360-nm light in the absence of psoralen, or treated with the intercalating agents ethidium bromide, 9-aminoacridine, ICR-191, or actinomycin D, responds to the enzyme no differently from untreated DNA. However, DNA crosslinked with mitomycin C or nitrogen mustard behaves similarly to psoralen-treated DNA. The relationship of these findings to models for the function and control of the recBC ATPase and nuclease, and the advantages of psoralen as a DNA crosslinking agent, are discussed.
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PMID:Uncoupling of the recBC ATPase from DNase by DNA crosslinked with psoralen. 426 6

Mild micrococcal nuclease treatment of rat and mouse nuclei and fractionation were based on the method of Tata and Baker. Three chromatin fractions, S, P1, P2, were separated, and for each of these fractions the sensitivity to the DNase 1 action was determined. The relative content in these fractions of non-transcribed DNA sequences was established by hydridization with a mouse satellite DNA, and the relative content of transcribed DNA sequences--by hydridization with DNA synthesised on the total poly (A) mRNA. None of the fractions displayed the properties characteristic of active chromatin.
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PMID:[Fractionation of chromatin of liver cell nuclei after mild micrococcal nuclease digestion]. 612 59

Phosphatidylserine (PS) and phosphatidylcholine (PC) multilamellar vesicles (MLV) affect chromatin structure as analysed by DNase I sensitivity. The kinetics of DNA solubilisation during the digestion of nuclei indicates that phosphatidylserine causes an increase in DNase accessibility while phosphatidylcholine slightly reduces this accessibility. The effect of phosphatidylserine has also been analysed by means of isokinetic sucrose gradients and agarose gel electrophoresis of nuclear DNA solubilised by micrococcal nuclease. This analysis indicates that phosphatidylserine induces a very rapid production of mononucleosome subunits as compared with untreated nuclei.
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PMID:Response of isolated nuclei to phospholipid vesicles: analysis of chromatin sensitivity to DNase I and micrococcal nuclease. 623 Nov 16


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