Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.21.1 (DNase)
 7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The methylation status of hepatitis B virus (HBV) DNA was investigated in different organs from two strains of transgenic mice (E36 and E11) expressing the hepatitis B surface antigen (HBsAg) gene specifically in the liver. Specific sites in the S gene were shown to be methylated in all the organs of adult mice except in the liver. These sites were methylated in 14-day-old fetal liver and were progressively demethylated during development and after birth. In one strain in which HBsAg expression is lost upon transmission by females, extensive de novo methylation of the transgene was detected in the livers and bodies of 14-day-old fetuses from transgenic females. The extent of methylation was such that activation of the gene was no longer possible. DNase I-hypersensitive sites were detected in the enhancer region of HBV in the liver of HBsAg-positive mice but not in HBsAg-negative progeny of E36 females. These data indicated that in two independent transgenic lines, HBV sequences are reproducibly activated in the developing liver along with cellular liver-specific genes and that transcription is associated with demethylation at specific sites in the S gene and with DNase hypersensitivity.
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PMID:Transcription of the S gene in transgenic mice is associated with hypomethylation at specific sites and with DNase I sensitivity. 229 89

We have determined the DNA sequences in the J2-C2 intron of the T cell receptor (TCR) beta gene and analyzed nuclear proteins binding to this region. Previously, we identified two tissue-specific DNase I hypersensitive regions, potential regulatory regions, in the J-C intron. The DNA sequence of the J2-C2 intron revealed that both DNase I hypersensitive regions have similar DNA sequences, suggesting that these regions are evolutionarily conserved. We have also identified tissue-specific nuclear-protein binding regions downstream of the DNase hypersensitive regions. Although transcriptional enhancer activity was not observed in the hypersensitive regions or the adjacent protein binding regions in the J-C intron, our findings suggest that the TCR-beta J-C intron may contain some other type of regulatory element.
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PMID:Identification of tissue specific nuclear proteins: DNA sequence and protein binding regions in the T cell receptor beta J-C intron. 234 98

We have devised a zymogram method with high sensitivity and resolution for investigating molecular heterogeneity and genetic polymorphism of deoxyribonuclease I. A combination technique of polyacrylamide-gel isoelectric-focusing electrophoresis and the newly developed zymogram method have led to the discovery of genetic polymorphism of human serum DNase I. Family studies showed that the three common phenotypes--DNASE1 1, DNASE1 1-2, and DNASE1 2--and the other five relatively rare phenotypes--DNASE1 1-3, DNASE1 2-3, DNASE1 2-4, and DNASE1 3-4--represent homozygosity or heterozygosity for four autosomal codominant alleles, DNASE1 *1, DNASE1 *2, DNASE1 *3, and DNASE1 *4. The frequencies of DNASE1 *1, DNASE1 *2, DNASE1 *3, and DNASE1 *4 calculated in a Japanese population were .5517, .4358, .0104, and .0021, respectively. Moreover, it was found that urine and extracts of kidney, liver, and pancreas, as well as serum, can be used for DNase I phenotyping.
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PMID:Human serum deoxyribonuclease I (DNase I) polymorphism: pattern similarities among isozymes from serum, urine, kidney, liver, and pancreas. 234 40

In patients with pancreatic cancer deoxyribonuclease I (DNase I) serum levels were compared with those of other known pancreatic enzymes. Serum deoxyribonuclease I, elastase 1, immunoreactive trypsin, amylase and phospholipase A2 were determined in 40 healthy controls, 28 patients with pancreatic cancer, 49 with chronic pancreatitis and 40 with extra-pancreatic diseases. The analysis of variance showed a significant difference among groups for serum DNase I values. However, none of the 3 groups of patients had a mean deoxyribonuclease I value higher than that of the healthy controls. In pancreatic cancer and chronic pancreatitis patients, increases in the 4 pancreatic enzymes values were found in percentages that were higher than those for DNase I. A significant correlation was found between DNase I and phospholipase A2, but not between DNase I and elastase 1, immunoreactive trypsin and amylase serum activities. The findings indicate that deoxyribonuclease I serum determination is an even less satisfactory index of pancreatic malignancy than the other pancreatic enzymes. Rather than expressing pancreatic damage, any variations in this enzyme appear more likely to reflect an aspecific phenomenon.
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PMID:Deoxyribonuclease I serum activity in pancreatic cancer. 235 55

We have previously identified a series of five DNase-I hypersensitive (HS) sites within and around the rat phosphoenolpyruvate carboxykinase (PEPCK) gene. The far upstream region has now been sequenced, and the tissue-specific HS site has been mapped more precisely at 4,800 base pairs upstream of the transcription start site of the PEPCK gene. DNA fragments that include the HS site were cloned upstream of various promoters to test whether these regions modulate transcription of the chloramphenicol acetyltransferase reporter gene. Chloramphenicol acetyltransferase activity was enhanced when the DNA fragment encompassing the upstream HS site was linked to various lengths of the PEPCK promoter or to the heterologous simian virus 40 promoter. This upstream region in conjunction with the proximal promoter, which may contain a tissue-specific element, conferred maximum activation in H4IIE hepatoma cells, which express the endogenous PEPCK gene. When these experiments were performed in XC cells, in which the gene is not expressed, transcriptional activation by the upstream element was still significant. Evidence of a specific protein-DNA interaction, using DNA mobility shift and DNase I footprinting assays, was obtained only when using H4IIE cell nuclear extracts. Competition assay showed that the interacting factor may be similar or identical to the liver-specific factor HNF3. We suggest that this protein factor binds to DNA within the HS site and interacts with the proximal promoter region to control tissue-specific high-level expression of the PEPCK gene.
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PMID:Interaction of a liver-specific factor with an enhancer 4.8 kilobases upstream of the phosphoenolpyruvate carboxykinase gene. 235 22

The Philadelphia (Ph1) chromosome (22q-), found in more than 90% of patients with chronic myeloid leukemia (CML), is one part of a reciprocal translocation, t(9;22) (q34;q11), in which the oncogene c-abl moves from 9q34 to 22q11. The translocation results in the translation of an aberrant abl-related protein with tyrosine kinase activity. Genetically active genes are known to have chromatin which is hypersensitive to deoxyribonuclease I (DNase I) and to be hypomethylated. Using an in situ nick translation technique on metaphase chromosomes, we have examined DNase I sensitivity and methylation status at the breakpoints 9q34 and 22q11 in bone marrow cells from controls (two cases) and CML patients (three cases). In CML cells DNase I sensitivity was significantly increased, at both breakpoints, in the translocated chromosomes compared with their normal homologues in CML cells and with both homologues in control marrows. A hypermethylated site, seen at 22q11 in normal 22s was hypomethylated on 22q-. The 9q34 region was hypomethylated in normal and translocated chromosomes. DNase I sensitivity, seen at 22q13 in CML cells, was lost following translocation in one of three cases. This technique demonstrates alterations in chromatin conformation and methylation status at translocation breakpoints which may be related to acquired genetic activity at one or both of these sites.
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PMID:Possible evidence for acquired genetic activity at both chromosomal breakpoints of the Philadelphia translocation in chronic myeloid leukemia. 238 79

We have analysed the chromatin features of DNA regions encompassing human epsilon, G gamma, A gamma, delta and beta globin structural genes in fetal and adult erythroid cells on the one hand and adult lymphocytes on the other. Highly purified nuclei from these cells were submitted to DNase I digestion and the kinetic data were obtained from the percentage of residual hybridization of defined regions in Southern blots. Our results, as others have shown by different approaches, indicate that the structural genes of the beta-globin cluster are generally more sensitive to DNase I in the erythroid cells than in non-erythroid cells. Thus a domain of DNase I sensitivity related to the committed state is defined. In addition we show that within this DNase-I-sensitive beta cluster domain, individual genes of the cluster are arranged in subdomains of differential DNase I sensitivity, which correlate with their expression status. Furthermore the differential expression of the two fetal genes in the fetal stage is shown to be directly proportional to the degree of hypomethylation of these genes.
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PMID:Differences in DNase I sensitivity and methylation within the human beta-globin gene domain and correlation with expression. 242 May 88

We have prepared three types of RNA polymerase II transcription complexes: a preinitiation complex (complex 0), a complex which has synthesized two phosphodiester bonds (complex 2), and a complex which has synthesized 10-13 bonds (complex 10). We have studied the differential response of these complexes to a variety of disruptions: detergent (Sarkosyl), high levels of KCl, extended incubation at 25 degrees C, proteolysis, and digestion with DNase I. Complex 0 is extremely stable at 25 degrees C in the absence of ATP, but it is sensitive to the other treatments including 25 degrees C incubation in the presence of ATP. Once the complex has made two phosphodiester bonds, the properties almost reverse from those of complex 0; complex 2 remains unstable at 25 degrees C in the presence of ATP but is resistant to high levels of Sarkosyl and KCl, to extensive DNase I digestion, and to brief proteolysis. Addition of 10 or more bases to the growing RNA chain results in a complex completely resistant to all of the treatments used. When DNase I-trimmed complex 0 is allowed to initiate RNA synthesis, chains of about 33 bases are obtained. In contrast, DNase-trimmed complex 2 gives only about 23 base transcripts; DNase-treated complex 10 will elongate its nascent chains by about 21 bases as well (to give, on average, 34 base transcripts).
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PMID:Transcription initiation by RNA polymerase II in vitro. Properties of preinitiation, initiation, and elongation complexes. 243 61

Ca uptake by isolated SR membranes is inhibited by a cytosolic factor derived from heart cells. The inhibitory activity resides in the fraction of soluble proteins which precipitates in 30% saturated (NH4)2SO4 [Narayanan et al. (1982) Biochem. Biophys. Res. Commun. 108, 1158-1164]. In the present study, the mechanism of inhibition and the properties of the inhibitor have been analysed. The cytosolic inhibitor activates a Ca-release pathway, thereby uncoupling Ca loading and Ca-dependent ATPase activity of SR vesicles. Analysis of some general physiochemical characteristics of the endogenous inhibitor (e.g. thermolability, protein profile, solubility properties, interaction with ion-exchange resins) showed it to be distinct from free fatty acids which might contaminate the cytosolic fraction. Rather, it indicated that the inhibitor is related to myofibrillar or cytoskeletal structures. By means of an affinity-chromatography procedure using muscle albumin coupled to Sepharose 4B, a protein component was obtained from the inhibitor fraction. The characteristics of this protein closely resembled those of the endogenous inhibitor. A protein with similar characteristics was also obtained using a DNase-I-affinity chromatography column. The isolated protein was identified as actin. Inhibition of Ca uptake by the isolated inhibitor protein was reversed by muscle albumin and by stoichiometric amounts of DNase I. The potency of inhibition of various actin preparations was found to be highly variable and dependent on the tissue source. Our results indicate that particular minor actin isoforms present in heart cytosol display the greatest inhibitory activity (IC50 15-20 micrograms/ml).
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PMID:Characterization of heart cytosolic proteins capable of modulating calcium uptake by the sarcoplasmic reticulum. 2. Identification of actin isoforms with inhibitory activity. 243 34

Active human ribosomal gene clusters (NORs) are distinguishable from inactive ones by silver staining. By sequentially applying deoxyribonuclease I (DNase I)-directed in situ nick-translation and silver staining to fixed chromosome preparations, we found that active NORs are more sensitive to DNase I than inactive ones. Use of the two restriction isoschizomeres MspI and HpaII to modify the nick-translation technique showed that active NORs are significantly less methylated than inactive ones. Taken as a whole, our results indicate that ribosomal gene activity, DNase I sensitivity, and DNA methylation are closely interrelated.
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PMID:Human NORs show correlation between transcriptional activity, DNase I sensitivity, and hypomethylation. 245 83


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