Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This investigation sought to characterize biochemically the tumor-specific transplantation antigens (TSTA) expressed on the cell surface of a panel of chemically induced fibrosarcomas of C3H/HeJ mice. Results suggest a uniform antigenic framework upon which individual specificities are superimposed. The antigens expressed by the 3-methylcholanthrene-induced fibrosarcomas MCA-D, MCA-F, and MCA-2A fulfill the requirements of a TSTA; namely, immunization of syngeneic hosts with irradiated cells or soluble extracts engenders a tumor-specific immune response such that animals resist challenge with the same, but not another, tumor. Brief incubation of intact tumor cells in single-phase aqueous solutions of 2.5% (v/v) 1-butanol extracts an immunoprotective TSTA, but not alloantigenic activity, from MCA-F cells. This extraction protocol was extended to the two other MCA-induced neoplasms. The butanol-extracted TSTA from the three tumors displayed isoelectric pHs of 6.4 to 6.6 following preparative isoelectric focusing. The tumor-specific immunoprotective activity from all three tumors displayed an apparent molecular weight of 150,000 (150 kDa) during high-performance gel permeation chromatography. The chromatographic properties of the 150 kDa antigens were unaffected by reduction using dithiothreitol, but incubation in acetate buffer, pH 3.0, dissociated the 150 kDa complex into at least two components with molecular weights of 70 to 100 kDa and 20 to 40 kDa. Only the smaller component displayed TSTA activity. The presence of two major components in the 150-kDa antigen was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. TSTA activity was sensitive to digestion with pronase, papain, chymotrypsin, and alpha-mannosidase, but resistant to DNase, RNase, neuraminidase, trypsin, endoglycosidase H, and a mixed-function glycosidase. In addition, the TSTA activity was unaffected by heating. These data demonstrate that MCA carcinogenesis results in the expression of immunologically unique epitopes on biochemically related glycoproteins and suggest a unified mechanism for the generation of TSTA polymorphism.
 ...
PMID:Biochemical characterization of 1-butanol-extracted murine tumor-specific transplantation antigens. 240 45

A macromolecule binding 3H-methylcholanthrene (3H-MCA) and 3H-benzo(a)pyrene (3H-BaP) and sedimenting in the 4-5 S region of sucrose gradient (4.5 S) was identified in rat liver cytosol. The binding was displaced by 100-fold molar excess unlabeled ligands whereas 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) was ineffective. The dissociation constant for both polycyclic aromatic hydrocarbons (PAHs) was of the order of 10(-8) M or lower. Both 3H-MCA and 3H-BaP bound to 4.5 S in a non covalent manner, since 92% of the bound radioactivity was extractable with ethyl ether. Furthermore the binding was strongly reduced by urea 8 M and by guanidine. HCl 4 M (99 and 70% respectively). Thin layer chromatography of the ethyl ether-solubilized radioactivity showed a peak comigrating with PAHs used as standards. When chromatographed on Sephadex G-200, 4.5 S was eluted as a sharp peak with an apparent molecular weight of 50-60,000 daltons. Enzyme treatment of liver cytosol showed that the 4.5 S binding sites were destroyed by micrococcal nuclease (92% of inhibition). Papain and phosphodiesterase I and II reduced the binding to 50%, whereas DNase I, DNase II, RNase, phospholipase A2 and C and trypsin were ineffective. These data suggest that the PAHs binding macromolecule of rat liver cytosol is a protein associated with a polynucleotide. The binding of both PAHs was enhanced by increasing the incubation temperature, the maximum being reached after 20-30 min at 37 degrees C. After 2.5 min at 65 degrees C, binding sites were completely destroyed. The same temperature-induced "activation" was obtained also by prewarming the cytosol at 37 degrees C in the absence of ligands.
 ...
PMID:Polycyclic aromatic hydrocarbon binding macromolecules. Identification, characterization and temperature activation of a 4.5 S binding nucleoprotein. 406 Feb 44

A tumor-derived suppressor factor ( TDSF ) has been isolated from 3 M KCl extracts of a chemically induced fibrosarcoma of C3H/HeJ mice by preparative isoelectric focusing. Incubation of TDSF with normal spleen cells induces suppressor cells that enhance tumor growth and inhibit DTH to the chemical sensitizer 2,4-dinitro-1-chlorobenzene (DNCB). Similar suppressogenic activity has been detected in extracts of the 10T1/2 fibroblast line, an ultraviolet-induced fibrosarcoma of C3H/HeN mice, the C57B1/6J Lewis lung carcinoma, and four human colonic adenocarcinoma. TDSF activity was not found in extracts of syngeneic muscle or spleen cells. Chemical characterization of TDSF from the murine fibrosarcoma MCA-F revealed sensitivity to treatment with heat and RNase, partial sensitivity to treatment with trypsin, but resistance to treatment with DNase, pronase, and neuraminidase. TDSF has an apparent molecular weight of greater than 300 kDa by high-performance gel permeation chromatography. Acidic soluble factors isolated from murine and human tumors induce suppressor cells to inhibit cell-mediated immunity in an intact host.
 ...
PMID:Soluble factors from murine and human tumors induce suppressor cells. 653 7

The previous report described the cloning kinase R1 cDNA [Uchida, T. and Yamashita, S. (1992) J. Biol. Chem. 267, 10156-10162]. A new cDNA, for choline kinase R2, was isolated from rat liver cDNA libraries. This transcript was thought to be generated by alternative splicing. Ribonuclease protection analysis revealed the presence of a third choline kinase. Three transcripts were detected in all of the examined rat tissues at different levels. Southern blot analysis demonstrated a single copy of choline kinase R gene. The genomic DNA containing the first exon and its flanking regions of choline kinase R gene was isolated and characterized. A number of transcription start sites, determined by ribonuclease protection and primer extension analyses, were found. The most 3' site, 193 base pairs upstream of the initiation codon and common in liver and testis, was the main site in liver. Some transcription start sites were detected only in testis. Choline kinase R gene showed features not only of a typical housekeeping gene but also of a gene regulated through a variety of putative cis-acting motifs. 3-Methylcholanthrene and carbon tetrachloride increased all of three transcripts to various levels, and enhanced transcription from the same start site, which scarcely gave a detectable product in normal liver.
 ...
PMID:Regulation of choline kinase R: analyses of alternatively spliced choline kinases and the promoter region. 785 67