Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The simian sarcoma virus (SSV) encodes a gag-related 65,000-Da protein (SSV p65) which is not processed in SSV nonproducer cells (SSV-NP cells) (H.-J. Thiel, T. J. Matthews, E. M. Broughton, K. J. Weinhold, D. P. Bolognesi, T. Graf, and H. Beug (1981a), Virology 114, 124-131). In order to cleave SSV p65, retroviral particles containing this antigen were incubated with extracts from the heterologous helper virus Friend leukemia virus (FLV). Superinfection of SSV-NP cells by FLV has been previously shown to result in processing of SSV p65 in vivo (H.-J. Thiel, F. Weiland, R. Hafenrichter, T. J. Matthews, and K. J. Weinhold (1982), Virology 123, 229-234). In vitro cleavage was most efficient in the presence of a nonionic detergent (greater than 0.1% Nonidet-P40) and a reducing agent (greater than 5 mM dithiothreitol) at a pH of 7.0. The products, termed SSV p55 (p15, p12, p30), SSV p30, SSV p25 (p15, p12), and SSV p10, were characterized by (1) molecular weight, (2) kinetics experiments, (3) incorporation of different radiolabeled amino acids, and (4) comparison with SSAV structural proteins. Kinetics experiments with two amino acids ([3H]leucine, [35S]cysteine) revealed that initial processing of SSV p65 produced SSV p55 and SSV p10, with subsequent processing of SSV p55 occurring thereafter. In contrast to the Moloney system, the major intermediate p40 (p30, p10) could not be clearly demonstrated. A direct comparison of SSAV p10 and the cleavage product SSV p10 by SDS-PAGE suggests that SSAV pr65gag and SSV p65 differ slightly by molecular weight.
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PMID:Simian sarcoma virus-encoded gag-related protein: in vitro cleavage by Friend leukemia virus-associated proteolytic activity. 299 99

The plasminogen activator (PA) in clonal osteogenic sarcoma cells of rat origin (UMR 106-01 and UMR 106-06) and in osteoblast-rich rat calvarial cells has been characterized using specific antibodies to be tissue-type PA (tPA). An Mr value of 75,000 by SDS-polyacrylamide gel electrophoresis and fibrin autoradiography supports this characterization. There was also evidence for an Mr 105,000 component, which could be due to a proteinase-inhibitor complex. The mechanism of regulation of this tPA activity has been studied in the clonal osteogenic sarcoma cells. Parathyroid hormone (PTH) and prostaglandin E2, which increase cyclic AMP production in the sarcoma cells, also increased tPA activity. The sensitivity and magnitude of the tPA response to PTH and prostaglandin E2 were increased by simultaneous treatment with isobutylmethylxanthine (IBMX) at drug concentrations which had little effect themselves on tPA activity. In UMR 106-06 cells, which unlike UMR 106-01 cells show a cyclic AMP response to calcitonin, tPA activity was also increased in response to calcitonin, and the effect was enhanced by IBMX. 1,25-Dihydroxyvitamin D-3 also increased tPA activity in the cells, but this response was not modified by IBMX. Synthetic peptide antagonists of PTH-responsive adenylate cyclase, [34Tyr]-hPTH (3-34) amide and [34Tyr]-hPTH (5-34) amide, inhibited the PTH-induced increase in tPA activity over the same concentration range at which they inhibited cyclic AMP production, but the antagonist peptides had no effect on the tPA responses to prostaglandin E2, calcitonin or 1,25-dihydroxyvitamin D-3. These data indicate that cyclic AMP mediates the actions of PTH, prostaglandin E2 and calcitonin in increasing tPA activity in the clonal osteogenic sarcoma cells. 1,25-Dihydroxyvitamin D-3, on the other hand, increases tPA activity through a mechanism independent of cyclic AMP.
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PMID:Cyclic AMP-dependent and -independent effects on tissue-type plasminogen activator activity in osteogenic sarcoma cells; evidence from phosphodiesterase inhibition and parathyroid hormone antagonists. 301 47

Sarcolectins are present in a great variety of tissues from mammalian origin. Such substances were observed to be secreted from cultures of human embryonic fibroblasts, human osteosarcoma and rat Rous sarcoma transformed cells and could be extracted from TG 180 Crocker Sarcoma or normal human placenta. All sarcolectins tested here, were comparable by their physicochemical properties to those previously reported in hamster or human sarcomas. Indeed, they are proteins or glycoproteins, resistant to pepsin and migrate in SDS-PAGE in the 65 kDa area. They agglutinate cells with an affinity for simple sugars and degrade previously established interferon-induced antiviral resistance. Considering the hamster sarcolectin as reference in this comparative study, both differences and similarities in the antigenic properties of mouse, rat and human sarcolectin variants were demonstrated. An indirect immunofluorescence assay showed that sarcolectins were specifically labelled on the cell surface but not detected in the cytoplasm after methanol or acetone permeabilization of the membrane. By electron microscopy, using immunoperoxidase labelling, sarcolectins can be localized on the surface of normal, transformed, human or rat cells. Only limited segments of normal cell membranes were labelled, while transformed cells were frequently stained on their whole surface. Other known extracellular proteins, such as fibronectin and collagen, did not share common antigenic determinants with sarcolectins.
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PMID:Cell distribution and antigenic properties of mammalian sarcolectins. 311 55

A rapid and sensitive method was developed for the preparative separation of laminin subunits. Laminin was extracted and purified from mouse EHS sarcoma. On SDS-PAGE, the reduced and carboxymethylated molecule separated into two components corresponding to molecular weights of about 400 KDa (subunit A) and 200 KDa (subunit B). These two subunits were preparatively separated using heparin-agarose affinity chromatography. The larger subunit quantitatively adhered to the affinity column while the smaller one did not adhere. Amino acid analyses of the separated subunits showed distinct differences. Subunit B was further resolved into two distinct polypeptides of 200 KDa, B1 and B2, by means of reverse-phase HPLC. Although the amino acid compositions of B1 and B2 were very similar, the peptide maps generated by digestion of the B1 and B2 chains with Staphylococcus aureus V8 protease or by cyanogen bromide showed B1 and B2 to differ from each other. Thus, at least three different polypeptide subunits are present in this laminin and probably arise from separate gene origins. These studies provide a basis for the subsequent localization and analysis of the specialized structural and functional domains of laminin.
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PMID:Separation and characterization of the subunits of the laminin of EHS sarcoma. 320 18

Monoclonal antibodies were produced by immunization of the human glioma cell line SK-MG-4. One of the antibodies, designated G-22, reacted with 18 of 20 glioma cell lines, two melanoma cell lines, and three lung cancer cell lines, but not with 39 cell lines derived from sarcoma, carcinoma, or hematopoietic tumors. The antigen was expressed in the brain of human fetuses in early gestation (9 weeks) but not in late gestation (8 months) or in normal adult brain, suggesting that the antibody recognizes neural differentiation antigens expressed by neuroectodermal origin. A high incidence of positive antigens has been observed in gliomas but not in the other neural tumors, such as ependymomas, meningiomas, and neuroblastomas. Thus, the antigen defined by the G-22 monoclonal antibody could be defined as glioma-associated antigen. Pulse-labeling with tritiated leucine and subsequent immunoprecipitation of the solubilized cell membrane revealed that the antigen recognized by this antibody had a molecular weight of 67 kD on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). It was shown by dot-blot enzyme-linked immunospecific assay (ELISA) that the antigen could be detected in the cerebrospinal fluid (CSF) from patients with gliomas. From analysis of affinity chromatography and SDS-PAGE, the antigen present in the CSF had a molecular weight similar to that of a 1% Nonidet P-40 (NP-40) extract from a glioma cell line. When the antigen in CSF was quantitatively assayed by ELISA, the mean antigen level (expressed as optical density at 450 nm) in the CSF of seven patients was 0.8 +/- 0.28 (mean +/- standard deviation), which was significantly higher than the 0.38 +/- 0.14 level observed in the CSF of 15 patients with nonglioma brain tumors and the 0.23 +/- 0.09 level in the CSF of four patients without brain tumors. These results indicate that the monoclonal antibody G-22 is useful for the diagnosis of glioma.
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PMID:Characterization of neuroectodermal antigen by a monoclonal antibody and its application in CSF diagnosis of human glioma. 334 15

The optic nerve of the developing rat was examined for the presence of laminin, an adhesive glycoprotein, to assess whether it might serve as a substrate for retinal axon growth in vivo. The optic stalk and nerve of developing rats were screened immunohistochemically for the presence of laminin before, during, and after the period of retinal axon growth. On embryonic day 14 (E14), laminin immunoreactivity was present in the ventral portion of the optic stalk, the same region in which the first retinal axons grow. Between E16 and postnatal day 10 (P10), cells positive for laminin were distributed throughout the cross-sectional area of the nerve. There was a progressive appearance of glial fibrillary acidic protein (GFAP) immunoreactivity, a marker for astrocytes, from the optic nerve head towards the chiasm beginning on E20. At the advancing front of GFAP immunoreactivity, cells were positive for both laminin and GFAP. Behind the front, laminin immunoreactivity disappeared from the cells. By P12, the only laminin immunoreactivity that remained within the optic nerve surrounded the vasculature. This is a time after the last retinal axons grow through the optic nerve. Monolayer cell cultures were prepared from perinatal rat optic nerves and processed for immunohistochemistry to determine which astrocyte type was laminin-positive. Type 1 astrocytes, which primarily compose the immature nerve, are GFAP-positive, A2B5-negative, and laminin-positive. Type 2 astrocytes, a major component of the mature optic nerve, were GFAP-positive, A2B5-positive and laminin-negative. An extract of developing optic nerve was analyzed by immunoblot along with laminin purified from Engelbreth-Holm-Swarm (EHS) sarcoma. Purified laminin ran with SDS-PAGE under reducing conditions as 2 bands with Mrs of 200,000 and 4000,000. Both bands reacted with antibodies to laminin. A low-salt extraction of whole optic nerve from E18 rats resulted in 2 bands with the same Mr as seen with laminin from EHS sarcoma. When only the inside of the optic nerve (which lacked the basal lamina and meninges that surround the outside) was processed, there was a dark 200,000 D band, but the 400,000 D band was virtually absent. These results are consistent with the hypothesis that laminin, or a variant form of laminin, serves as a substrate for retinal axon growth in the developing rat optic nerve.
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PMID:Transient expression of laminin in the optic nerve of the developing rat. 338 86

GMP synthetase was found in the cytosolic fraction of Yoshida sarcoma ascites cells. However, prolonged centrifugation resulted in precipitation of the enzyme. On sucrose density gradient centrifugation of a crude extract of Yoshida sarcoma ascites cells, a part of this enzyme showed high sedimentability at low ionic strength. On the basis of these observations, GMP synthetase was purified from Yoshida sarcoma ascites cells by means of procedures including centrifugal fractionation. The purified enzyme was shown to be homogeneous on SDS-polyacrylamide gel electrophoresis and isoelectric focusing in polyacrylamide gel. The molecular weight of the GMP synthetase was estimated to be 78,000 by SDS-polyacrylamide gel electrophoresis and gel filtration on Sephadex G-150. Its isoelectric point was estimated to be 5.6. The Km values of this enzyme for XMP, ATP, and glutamine were calculated to be 4.6, 120, and 300 microM, respectively. Although ammonia could substitute for glutamine as a donor of the amino group, the Km value was as high as 120 mM, indicating that it cannot be considered to be a physiological substrate. This enzyme showed high activity only in the presence of Mg2+, and very low activity in the presence of other divalent cations. Inhibition by nucleoside monophosphates was not significant. The enzyme required reduced sulfhydryl compounds for its activity.
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PMID:Purification and characterization of GMP synthetase from Yoshida sarcoma ascites cells. 343 58

Peritoneal macrophages from mice bearing a transplantable methylcholanthrene-induced sarcoma produced progressively less IL 1 as tumor burden increased. The loss of activity was not explained by the production of any inhibitor of the mouse thymocyte comitogen bioassay. Immune precipitation with a polyclonal antibody confirmed the decline in IL 1 appearance. Although tumor-bearing animals lost approximately 17% of their carcass mass, the reduced production of IL 1 was not satisfactorily explained by coexistent malnutrition, since similarly depleted non-tumor-bearing mice were capable of producing IL 1. In addition to an altered IL 1 production by macrophages of tumor-bearing mice, SDS-polyacrylamide gel electrophoresis and autoradiography revealed that the pattern of secretory protein synthesis from LPS-stimulated and unstimulated peritoneal macrophages differed between tumor-bearing and control animals. Administration of LPS to tumor-bearing mice early after tumor transplantation resulted in reduced tumor growth and prevented the down-regulation of in vitro IL 1 production by peritoneal macrophages. These findings demonstrate a specific defect in IL 1 production associated with increasing tumor burden. Further studies are required to determine whether this defect in IL 1 synthesis contributes to the increased tumor growth.
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PMID:Down-regulation of interleukin 1 production by macrophages of sarcoma-bearing mice. 349 87

Transformation of NIH-3T3 fibroblasts by the Harvey murine sarcoma viral oncogene or by cultivation of fibroblasts under low serum conditions (spontaneous) resulted in the acquisition of hemolytic activity, as demonstrated by coincubation of the transformed fibroblasts with 59Fe-labeled red blood cells. The tumor Hemolytic Factor was partially purified from conditioned media produced by T-24 human bladder transformed fibroblasts by ammonium sulfate precipitation, followed by anion and gel filtration chromatography. The hemolytic factor has a molecular weight of 66,000 as documented by SDS-PAGE and is destroyed by heating to 60 degrees C.
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PMID:Purification of a hemolytic factor from ras oncogene transformed fibroblasts. 353 88

In order to screen human tumor cells for putative cell surface marker molecules, the glycoprotein composition of in vitro cultivated human tumor cell lines of different origin (12 carcinomas, one neuroblastoma, one melanoma and one sarcoma) was analyzed by metabolically labelling the cells with [3H]galactose, [3H]mannose and [3H]fucose and subsequently separating the labelled material by SDS-PAGE. The cell lines expressed their specific glycoprotein patterns. Strongly glycosylated proteins of apparent mol. wt 40-45 kD, 60-62 kD, 80-82 kD and 90-92 kD were shared by nearly all carcinoma cell lines studied. Apart from these glycoprotein clusters, a great diversity was observed between tumor cell lines derived from the same organ. Three bladder carcinoma cell lines had a 112-114 kD glycoprotein in common. Glycoprotein expression of these cell lines remained constant during 1 yr of in vitro culture. Hence, these glycoprotein patterns seem to be useful for monitoring the phenotypic stability of cell lines. A sarcoma cell line was deficient in incorporating fucose and showed strikingly different glycoprotein patterns compared to the other cell lines studied. The metabolic labelling procedure revealed a wide phenotypic heterogeneity of the human carcinoma cell lines concerning glycoprotein synthesis. This method contributes another parameter to map the major glycoprotein species of various types of carcinomas.
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PMID:Heterogeneity of glycoprotein synthesis in human tumor cell lines. 370 97


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