Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the control by hormones and culture conditions of the expression of pyruvate kinase L, aldolase B, and a liver-specific 5.4-kb mRNA species [Pichard, A. L. et al. (1985) Biochem. J. 226, 637-644] in three rat hepatoma cell lines, MH1C1, Fao and Faza. The expression level of these markers ranges from 2% (for pyruvate kinase L mRNA) to 10-12% (for 5.4-kb mRNA species) of the glucose-induced mRNA values found in rat liver. The mRNAs of the three liver-specific genes strongly decrease after treatment of the hepatoma cells with cyclic 8-bromo-AMP, cyclic dibutyryl-AMP or forkolin, pyruvate kinase L mRNA being the most sensitive to this inhibiting effect. In contrast, the concentration of pyruvate kinase L mRNA nuclear precursors is not modified by the cyclic AMP analogues, indicating that these agents do not act at the transcriptional level but, instead, probably destabilize the transcripts. Glucose or fructose does not modify the expression of these three marker genes in any of the studied cell lines. Insulin is inefficient in modifying concentrations of the mRNAs for pyruvate kinase L and aldolase B, alone or in the presence of carbohydrates. In contrast, it stimulates about fivefold the expression of the 5.4-kb mRNA species in the MH1C1 cell line; this stimulation is carbohydrate-independent. The hepatoma cell lines mimic, therefore, the effect of cyclic AMP on the inhibition in vivo of the expression of genes encoding glycolytic or lipogenic enzymes [Vaulont, S. et al. (1984) Biochem. Biophys. Res. Commun. 125, 135-147]. In contrast, the effect of carbohydrates [Munnich, A. et al. (1984) J. Biol. Chem. 259, 10228-10231] is undetectable. The insulin sensitivity of the liver-specific genes is conserved for the 5.4-kb mRNA species only, especially in the MH1C1 cell line, but not for the other investigated mRNAs, which seems to reflect a fundamental difference in the in vivo effect of insulin on these genes. Finally, S1 nuclease mapping of the start-site of pyruvate kinase L gene transcription shows that the normal site used in vivo is also used in the Fao and Faza lines while, in the MH1C1 line, it coexists with multiple aberrant upstream initiation sites.
 ...
PMID:Regulation of genes for glycolytic enzymes in cultured rat hepatoma cell lines. 369 93

A novel eucaryotic vector derived from the transforming region of bovine papilloma virus was established and demonstrated to be highly effective for introducing foreign genes into animal cells. The foreign deoxyribonucleic acid (DNA) is replicated and actively transcribed as an episome, and the transcripts are translated into an authentic gene product. We have constructed a DNA hybrid molecule, BPV69T-rI1, containing the transforming region of bovine papilloma virus DNA and the rat preproinsulin gene I (rI1), and used it to transform susceptible mouse cells. DNA hybridization analysis has demonstrated the presence of multiple unintegrated copies of hybrid DNA molecules, with the bovine papilloma virus 1 DNA segment and the rI1 gene covalently linked in selected transformed cell lines. S1 nuclease analysis revealed the presence of a correctly spliced coding segment of the preproinsulin transcript similar or identical in its electrophoretic mobility to that of messenger ribonucleic acid produced in rat insulinoma cells. Significant levels of a protein immunoreactive with anti-insulin serum were detected by radioimmunoassay in the culture medium of transformed cells. Immunoprecipitation analysis in conjunction with competitive binding to bovine proinsulin established the identity of the protein as that of rat proinsulin.
 ...
PMID:Bovine papilloma virus deoxyribonucleic acid: a novel eucaryotic cloning vector. 610 Sep 67

The expression of the insulin-like growth factors (IGFs) and their receptors has been linked to cellular proliferation and tumorigenicity in a number of model systems. Since rhabdomyosarcoma cells express IGF-I receptors, an autocrine or paracrine loop involving this receptor and its ligands could be responsible in part for the growth characteristics of this tumor. To assess directly the role of the IGF-I receptor in rhabdomyosarcoma cell growth and tumorigenicity, a human alveolar rhabdomyosarcoma cell line with high IGF-I receptor expression was transfected with an amplifiable IGF-I receptor antisense expression vector. Four unique, transfected clones were analyzed and found to have reduced IGF-I receptor expression relative to the parental line. Integration of the antisense sequence was demonstrated by Southern blot analysis, and expression of antisense message in these clones was shown by S1 nuclease protection assay. Reduced IGF-I receptor surface expression in the transfectants was shown by decreased immunofluorescence with an IGF-I receptor monoclonal antibody and by decreased IGF-I binding as measured by Scatchard analysis. These clones had markedly reduced growth rates in vitro, impaired colony formation in soft agar, and failed to form tumors in immunodeficient mice when compared with vector-transfected clones. These results demonstrate that reduction of IGF-I receptor expression can inhibit both the in vitro and in vivo growth of a human rhabdomyosarcoma cell line and suggest a role for the IGF-I receptor in mediating neoplastic growth in this mesenchymally derived tumor.
 ...
PMID:Antisense-mediated reduction in insulin-like growth factor-I receptor expression suppresses the malignant phenotype of a human alveolar rhabdomyosarcoma. 808 65

We have identified a novel antisense RNA transcribed from the insulin-like growth factor-II (IGF-II) locus in mouse. This transcript was identified using probes derived from cloned genomic DNA lying between the insulin II locus and the IGF-II locus. S1 protection assays confirmed that this transcript is transcribed from the strand complementary to the stand encoding IGF-II. A 3.75 kb RNA was consistently detected on northern analysis of mouse tissue using different randomly primed DNA probes generated from this region. S1 nuclease protection analysis identified three exons contained in the transcript. Developmental northern analysis was performed using RNA from embryonic (E) and postnatal (P) tissues of E10, E13, E18, P1, P4, P10, and adult mice. The antisense RNA was most abundant in E13 and E18 mouse and was present in greatest amounts in skull, skeletal muscle, cardiac muscle, and placenta. No signal for this RNA was detected after the fourth day of life in any tissue studied.
 ...
PMID:Identification of an antisense transcript from the IGF-II locus in mouse. 839 18

In vivo short term (2 h) insulin-regulated gene expression was examined in skeletal muscle of persons with differing insulin sensitivities. Nine genes were analyzed by a S1 nuclease protection assay with multiple probes (multiple S1 nuclease protection assay) to allow the simultaneous examination of RNA abundances from the multiple genes. In insulin-sensitive individuals, 5 of these 9 genes were insulin responsive. RNA from the proto-oncogenes c-Ha-ras, c-myc, and c-src transiently increased 2- to 4-fold within 30 min of insulin infusion. In addition, the RNA abundance of myf-5, a muscle specific differentiation factor, increased 3-fold with a time course similar to that of c-Ha-ras, c-myc, and c-src. In contrast, type 1 protein phosphatase alpha (PPP1A) RNA levels decreased by 50% within 30 min. In insulin-resistant individuals, the RNA levels of c-Ha-ras and myf-5 did not increase, whereas c-src RNA did increase within 30 min of insulin infusion. RNA encoding c-myc transiently increased in both groups; however, this response was lower in insulin-resistant individuals than in insulin-sensitive individuals in a pattern similar to c-Ha-ras and myf-5. PPP1A RNA levels slightly increased in insulin-resistant individuals. In both insulin-sensitive and insulin-resistant persons, RNA quantities of GLUT4, c-jun, c-fos, and the insulin receptor did not change over the period of insulin infusion. However, overall RNA levels of the insulin receptor and c-jun were lower in insulin-resistant individuals.
 ...
PMID:Insulin regulation of multiple ribonucleic acid species in human skeletal muscle in insulin-sensitive and insulin-resistant subjects. 863 61

The decanucleotides in a tandem repeat, -162 to -140 bp, are suppressor elements that decrease TSH receptor (TSHR) gene expression by different mechanisms. A factor(s) interacting with the 3'-decanucleotide compete for proteins that bind the cAMP response element, -139 to -132 bp, a constitutive enhancer necessary for efficient TSHR expression. The 5'-decanucleotide is in a CT-rich, S1 nuclease-sensitive region of the promoter; its suppressor activity has been related to its ability to bind a nonthyroid-specific protein to its coding strand. In this report we clone a complementary DNA encoding a single strand DNA-binding protein that forms a specific protein-DNA complex with the coding strand of the 5'- but not the 3'-decanucleotide and not with the 5'-decanucleotide noncoding or double strand. We show, by cotransfection with TSHR promoter-chloramphenicol acetyltransferase chimeras, that the protein is a suppressor that regulates the function of the 5'- but not the 3'-decanucleotide. The protein is a Y-box protein that was previously cloned as an enhancer factor from the rat liver; it is, however, 95% identical to human YB-1, which suppresses major histocompatibility class II gene expression, and to human nuclease-sensitive element protein-1, a Y-box protein identified by its ability to bind single strand, CT-rich, nuclease-sensitive elements of genes that, like the TSHR, have GC-rich promoters. Unexpectedly, the Y-box protein binds two other sites in the minimal TSHR promoter in a single strand-specific fashion and acts a suppressor at each of these sites. One is associated with the insulin response element of the minimal TSHR promoter and is not in an overtly CT-rich region. The other is located 3' to the cAMP response element in a region termed the S-box, -120 to -113 bp, because of its homology to the S-box of the major histocompatibility class II promoter; this site is in a CT-rich area and, as in the class II promoter, is linked to cAMP-induced gene suppression. A conserved CCTC sequence in each site is important for the binding and suppressor function of the Y-box protein.
 ...
PMID:A Y-box protein is a suppressor factor that decreases thyrotropin receptor gene expression. 883 47

Fatty acid transport protein (FATP) was identified by expression cloning strategies (Schaffer, J. E., and Lodish, H. F. (1994) Cell 79, 427-436) and shown by transfection analysis to catalyze the transfer of long-chain fatty acids across the plasma membrane of cells. It is expressed highly in tissues exhibiting rapid fatty acid metabolism such as skeletal muscle, heart, and adipose. FATP mRNA levels are down-regulated by insulin in cultured 3T3-L1 adipocytes and up-regulated by nutrient depletion in murine adipose tissue (Man, M. Z., Hui, T. Y., Schaffer, J. E., Lodish, H. F., and Bernlohr, D. A. (1996) Mol. Endocrinol. 10, 1021-1028). To determine the molecular mechanism of insulin regulation of FATP transcription, we have isolated the murine FATP gene and its 5'-flanking sequences. The FATP gene spans approximately 16 kilobases and contains 13 exons, of which exon 2 is alternatively spliced. S1 nuclease and RNase protection assays revealed the presence of multiple transcription start sites; the DNA sequence upstream of the predominant transcription start sites lacks a typical TATA box. By transient transfection assays in 3T3-L1 adipocytes, the inhibitory action of insulin on FATP transcription was localized to a cis-acting element with the sequence 5'-TGTTTTC-3' from -1347 to -1353. This sequence is very similar to the insulin response sequence found in the regulatory region of other genes negatively regulated by insulin such as those encoding phosphoenolpyruvate carboxykinase, tyrosine aminotransferase, and insulin-like growth factor-binding protein 1. Fluorescence in situ hybridization analysis revealed that the murine FATP gene is localized to chromosome 8, band 8B3.3. Interestingly, this region of chromosome 8 contains a cluster of three other genes important for fatty acid homeostasis, lipoprotein lipase, the mitochondrial uncoupling protein 1 (UCP1) and sterol regulatory element-binding protein 1. These results characterize the murine FATP gene and its insulin responsiveness as well as present a framework for future studies of its role in lipid metabolism, obesity, and type II diabetes mellitus.
 ...
PMID:Characterization of the murine fatty acid transport protein gene and its insulin response sequence. 976 71

Glucocorticoids regulate body energy balance through both peripheral and central mechanisms. In order to understand the central mechanisms that mediate these effects of glucocorticoids we studied the effects of adrenalectomy (ADX) and food deprivation on the expression of four neuropeptide genes (measured by S1 nuclease protection assay) in the medial basal hypothalamus (MBH), which are known to regulate energy balance: pro-opiomelanocortin (POMC), agouti-related peptide (AGRP), neuropeptide Y (NPY), and cocaine and amphetamine regulated transcript (CART). Adult male rats were ADX or sham operated (SHAM), and studied 1-2 weeks later. In the first study effects of ADX and corticosterone replacement on POMC and AGRP expression were determined. ADX decreased POMC and AGRP gene expression in the MBH by 27 and 38%, respectively, compared to SHAM rats. Corticosterone treatment increased the expression of POMC by 87% and AGRP by 45% in ADX rats. The second study was designed to determine if glucocorticoids are necessary for the fasting induced changes in POMC, AGRP, NPY and CART in the MBH. ADX caused a 20-30% decrease in the expression of all four neuropeptide genes in the MBH. As expected, fasting suppressed POMC and CART expression and increased AGRP and NPY expression. The fasting-induced increases in AGRP and NPY persisted after ADX but no further significant decreases in POMC or CART were noted after fasting in ADX rats. Plasma leptin and insulin declined significantly after ADX and increased with corticosterone replacement; both leptin and insulin declined further in fasted, ADX animals. In conclusion, ADX decreases both anorexigenic, POMC and CART, and orexigenic, AGRP and NPY, neuropeptide gene expression in the MBH. AGRP and NPY decrease after ADX despite the fall in plasma leptin and insulin concentrations which in other situations would increase these neuropeptides. Furthermore, glucocorticoids are not required for fasting-induced upregulation of AGRP and NPY expression.
 ...
PMID:Effects of adrenalectomy on AGRP, POMC, NPY and CART gene expression in the basal hypothalamus of fed and fasted rats. 1246 37

Aims-To determine the role of insulin-like growth factors (IGF) in the proliferation of tumour cells, by studying the mitogenic response to IGFs of three cell lines of differing phenotype established from both malignant rhabdoid and Wilms tumour, representing a range of cell types (GOS 4, G401, and T3/73).Methods-Production of IGF-II and IGF-I was measured by radioimmunoassay, and the presence of IGF binding protein complexes was observed by gel exclusion chromatography. Following growth analyses in serum-free media to ascertain the dependence of the cell lines on exogenous IGFs, the generation of autocrine growth was measured by a density dependence assay of proliferation in culture. Receptors were measured by radioligand cross linking and autocrine growth through these receptors assayed by the use of blocking antibodies.Results-While GOS 4 and G401 were able to proliferate in serum-free medium over a period of 5 d, T3/73 showed an absolute dependence on IGFs added daily at 1-10 ng/ml. Plating at clonal density showed that cell growth was directly density dependent in serum-free medium. The serum independent proliferation of G401 and GOS 4 was blocked by the addition of an antibody to the type 1 IGF receptor (alpha-IR3) suggesting that the effects of autocrine factors are mediated through type 1 IGF receptors. S1 nuclease protection analysis indicated that all three cell lines produced significant amounts of mRNA derived mainly from the P3 IGF-II promoter, but transcripts for IGF-I were undetectable. Radioimmunoassay of IGFs from conditioned media showed that all the lines made assayable IGF-II (8.6, 8.4, and 6.1 ng/ml/24 h/10(6) cells for GOS 4, G401, and T3/73 respectively). The presence of species consistent with both type 1 and type II IGF receptors was demonstrated using radioligand binding to cell membranes followed by cross linking.Conclusions-Autocrine IGF-II may contribute to the serum independence of GOS 4 and G401 cells, whereas T3/73 may depend on exogenous IGF-II for proliferation.
 ...
PMID:IGF-II dependent autocrine growth in cell lines derived from renal tumours of childhood. 1669 34


<< Previous 1 2