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)

Loose, fibrillar, spherical structures have been observed during recent years in interphase nuclei of both animal and plant cells. These nuclear formations have been referred to as karyosomes, fibrillar bodies, micropuffs and centromeres. In order to gain further information on the nature of these structures, a cytochemical and radioautographic investigation was undertaken using plant meristematic cells (Allium porrum). For that purpose roots were fixed with either formaldehyde or glutaraldehyde in order to carry out cytochemical tests for DNA, RNA and proteins. Certain of the preparations were also first digested with DNase, RNase or proteinase K and then stained according to different procedures. Other specimens were labelled with thymidine for high-resolution radioautographic observations. Staining with diaminobenzidine (DAB) revealed that these nuclear puff-like formations consisted partly of a loose fibrillar meshwork containing nucleic acids. Part of this fine fibrillar reticulum persisted whether the preparations were digested with DNase or RNase before staining with DAB, thus indicating that these nuclear structures contained both DNA and RNA. The fact that these formations incorporate thymidine furnished additional support for the view that they correspond to specific chromosome segments. Staining with ethanolic phosphotungstic acid or digestion of specimens with proteinase K showed that these loose fibrillar structures also consisted of proteins. Judging from their ultrastructure, their association with the chromatin reticulum as well as from their cytochemical characteristics, these nuclear formations most likely correspond to centromeres. In view of the presence of DNA within these structures, it is possible to distinguish them from other equally spherical nuclear formations, observed in certain plant species, that have generally been referred to as karyosomes or micronucleoli and that appear to consist of ribonucleoproteins.
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PMID:A cytochemical and radioautographic study of the ultrastructural organization of puff-like fibrillar structures in plant interphase nuclei (Allium porrum). 52 78

Low concentrations of formaldehyde (0,035 mg/m3) exert injurious effect on the testes. Changes were found in the RNA and DNA content, inhibition of deoxyribonuclease activity and reduced soluble protein content in testicular homogenate. Along with this, there was decrease in spermatozoid motility, indicating eventual weakening of the fecundating capacity of male rats. The parameters used, characterizing nuclein and protein metabolism in the testes, may serve as objective and very sensitive index in testing the gonadotoxic effect of low concentrations of chemical agents. The results of this study should be taken into consideration in making hygiene-toxicologic characteristics of formaldehyde, with special reverence to the threshold of its gonadotoxic effect.
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PMID:[Changes in protein and nucleic acid metabolism as 1 of the methods for evaluating gonadotoxic action]. 57 46

It is shown by enzymatic digestion of chromatin from rat liver or Guerin ascites tumour (GAT) that treatments, which abolish the 180 base pair repeat, as revealed by digestion with micrococcal nuclease (shearing in salt solutions of medium ionic strength, sonication, fixation with formaldehyde in the presence of 5 M urea), have little effect on the 10 nucleotide repeat, observed in deoxyribonuclease I digests.
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PMID:Persistence of the ten-nucleotide repeat in chromatin unfolded in urea, as revealed by digestion with deoxyribonuclease i. 96 74

We have studied by immunocytochemistry and monoclonal antibodies the presence and localization of estrogen receptors, progesterone receptors, and a 24-kD estrogen-regulated heat shock protein in biopsies from breast and endometrial cancer patients. Three different tissue processing protocols were used to colocalize the antigens in the same tissue sections: a) frozen sections, b) formalin fixation with routine paraffin embedding, and c) picric acid-formaldehyde (PAF) fixation with a rapid embedding in paraffin. Frozen sections showed good receptor staining but poor 24-kD protein immunoreactivity, while routine paraffin sections (with or without DNase pretreatment) were inadequate to reveal the nuclear receptor proteins at the same level seen in frozen sections. On the other hand, all three proteins could be detected satisfactorily in PAF-fixed paraffin-embedded tissue. Using this procedure we were able to visualize 24-kD protein and estrogen receptor or progesterone receptor in individual cells in paraffin sections. The study revealed that in all of the estrogen receptor positive breast and endometrial tumor samples, almost 90% of the cells expressing the cytoplasmic 24-kD protein contained estrogen receptor in the cell nucleus. In contrast, 24-kD immunoreactive cells did not express progesterone receptors in almost 40% of the progesterone receptor positive tumor samples.
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PMID:Colocalization of estrogen and progesterone receptors with an estrogen-regulated heat shock protein in paraffin sections of human breast and endometrial cancer tissue. 208 75

Ultraviolet light, formaldehyde, cis-diamminedichloroplatinum(II), chromate (Cr6+), or chromium chloride (Cr3+) under the appropriate conditions caused the formation of DNA-protein crosslinks in intact Chinese hamster ovary (CHO) cells or in cell nuclei. The DNA-protein crosslinks were isolated, applied to nitrocellulose filters, and reacted with antibodies to nuclear proteins. An antiserum to a 97-kD nuclear protein detected p97-DNA complexes in CHO nuclei and cell cultures treated with UV light, cis-Pt and formaldehyde. Exposure to Cr3+ induced p97-DNA crosslinks only in isolated nuclei, while chromate (Cr6+) treatment resulted in significant crosslink formation only in intact cells. Analysis of western blots with the p97 antiserum indicated that crosslinks induced by formaldehyde or ultraviolet light required DNAase I digestion of DNA for migration of the p97 complexes into the gel. In contrast, the 97-kD antigen from the metal-induced crosslinks was released from DNA and resolved in the gel when 2-mercaptoethanol was included in the electrophoresis sample buffer. Assay of slot blots with an antihistone monoclonal antibody indicated that formaldehyde, but not cis-Pt or chromate, crosslinked histones to the DNA. These results illustrate the utility of immuno-slot blots in detecting and characterizing DNA-protein complexes induced by diverse chemical and physical agents.
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PMID:Immunodetection of DNA-protein crosslinks by slot blotting. 232 90

Association of foreign DNA with chicken sperm cells was investigated using a 32P-oligolabelled plasmid preparation. Significant, although low, levels of trichloroacetic acid precipitable radioactivity became rapidly associated with viable sperm cells, in contrast to the situation with formaldehyde-fixed cells. However, analysis by Southern blotting and hybridization of sperm cells incubated with an unlabelled plasmid preparation followed by deoxyribonuclease 1 treatment, demonstrated associated foreign DNA was completely susceptible to nuclease degradation, whereas chromosomal DNA was not affected.
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PMID:Uptake and deoxyribonuclease 1 susceptibility of foreign deoxyribonucleic acid by chicken sperm cells. 236 75

Binding of the DNA-specific dye 7-aminoactinomycin D (7-AMD) in chromatin of human leucocytes was studied by flow cytometry. After formaldehyde fixation and permeabilization, monocytes bound 30-130% more 7-AMD than lymphocytes, while binding in granulocytes was 20-60% higher than in lymphocytes. Monocytes and lymphocytes bound similar amounts of 7-AMD when cells were permeabilized by detergent prior to fixation. Digestion of DNA in formaldehyde-fixed chromatin by DNase 1 was quantitated by measuring Hoechst 33258 (H33258) fluorescence of mononuclear cells. The monocyte/lymphocyte H33258 fluorescence ratio decreased with DNase 1 digestion to an asymptotic value of 0.74, showing that DNA in chromatin of monocytes was more susceptible to DNase 1 digestion. 7-AMD binding increased, reached a maximum and then decreased with extent of DNase 1 digestion in both mononuclear cell types. The monocyte/lymphocyte 7-AMD fluorescence ratio also decreased after DNase 1 digestion. RNA content and RNA synthesis were higher in monocytes than in lymphocytes. The results show that 7-AMD binding in chromatin of mononuclear leucocytes correlates with transcriptional activity as measured by DNase1 susceptibility and RNA synthesis. The staining procedure may be used for differential counting of mature myeloid cells in peripheral blood and bone marrow.
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PMID:Distinction of leucocyte classes based on chromatin-structure-dependent DNA-binding of 7-aminoactinomycin D. 244 92

In this report we describe a specific staining procedure for detection of ribonucleic acid (RNA), based on bromination of uracil and subsequent immunohistochemical visualization of 5-bromouracil in RNA. This method is applicable for both cryostat and glycol methacrylate (GMA)-embedded sections. Cryostat sections must be fixed in formaldehyde, whereas tissue pieces to be embedded in GMA are fixed in cold acetone. Before bromination, sections must be treated with trypsin. Bromination was performed in a solution of bromine in potassium bromide. After bromination, excess bromine was removed with sodium bisulfite. The monoclonal antibody MoBu-1 specifically bound to brominated RNA. Ribonuclease digestion, in contrast to deoxyribonuclease digestion, abolished staining. This method makes possible precise localization of RNA, especially well demonstrated in plastic-embedded sections.
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PMID:Specific demonstration of ribonucleic acid by chemical bromination and immunohistochemistry. 246 88

The proteins cross-linked to the DNA of cultured Chinese hamster ovary cells after exposure to cis-diamminedichloroplatinum(II) (cis-Pt), chromate, and formaldehyde were compared by two-dimensional (2D) gel electrophoresis, immunoblotting, and centrifugal assays that measured cross-link stability. Chromate and cis-Pt cross-linked seven of the same nonhistone proteins, such as actin, to DNA. In contrast, formaldehyde selectively formed histone-DNA cross-links. Immunoblotting experiments showed that all three chemicals cross-linked a 97-kDa nuclear protein to the DNA despite their different chemical reactivity with DNA and proteins. The chromate- and cis-Pt-induced cross-links were disrupted by thiourea, 2-mercaptoethanol, and EDTA, indicating that the metal could be chemically displaced from the cross-links. The formaldehyde-induced complexes required degradation with DNase 1 for the resolution of histones on 2D gels and were not chemically labile like the metal-induced cross-links. The agents and methodology used here could be applied to the study of additional nuclear proteins that bind or reside near the DNA.
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PMID:Analysis of proteins cross-linked to DNA after treatment of cells with formaldehyde, chromate, and cis-diamminedichloroplatinum(II). 261 69

Monoclonal antibodies (mAB) against progesterone receptor (PR) and the peroxidase-antiperoxidase (PAP) method to visualize PR in paraffin sections from 68 human breast cancers were used. Ten mAB, which recognize human PR on frozen sections, were tested. Six could detect PR in paraffin sections, with Li 417, LET 456, and LET 126 giving the best results. LET 126 antibody was used for most further studies. The effects of fixation with picric acid-formaldehyde (PAF), buffered-formalin, or with Bouin solution were investigated; all fixation methods allowed PR immunolabeling, although PAF or buffered formalin usually gave the best results. Positive staining was seen in the nucleus of carcinoma cells. Variations in intensity and extent of immunoreactivity were observed in all sections and among different regions of the same specimen. These were probably related to the heterogeneity of the tumor cell population. Results were compared with the PR content in the respective tumor tissues, determined by steroid-binding assay, and with immunocytochemistry on frozen sections. It was shown that there were correlations between the immunocytochemical staining (positive or negative) and the steroid binding assay (80%) and between the immunocytochemical staining on paraffin sections and on frozen sections (78%). Weaker intensity and fewer number of PR-positive cells were found for paraffin-embedded tumors. Estrogen receptors were also detected on adjacent sections from the same paraffin-embedded tissues by use of monoclonal anti-ER antibodies (ERICA-kit[Abbott Laboratories, Chicago, IL]) and DNase pretreatment. In conclusion, this immunocytochemical method for detection of PR and ER on paraffin sections offers an alternative to frozen tissue. It allows histologic and immunocytochemical studies on the same sample and retrospective studies on stored tissue blocks.
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PMID:Immunocytochemical staining of progesterone receptor in paraffin sections of human breast cancers. 267 23


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