Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previously we isolated and characterized a differentially expressed gene from mouse 3T3-L1 preadipocytes that encodes stearoyl-CoA desaturase (SCD1; Ntambi, J. M., Buhrow, S. A., Kaestner, K. H., Christy, R. J., Sibley, E., Kelly, T. J., Jr., and Lane, M. D. (1988) J. Biol. Chem. 263, 17291-17300). Genomic Southern blot analysis indicated the existence of another closely related gene. Here we report the isolation and characterization of this gene and the corresponding cDNA which encode a second stearoyl-CoA desaturase, SCD2, 3T3-L1 adipocytes. SCD2 cDNA is 5 kilobase pairs in length and encodes a protein of 358 amino acids with greater than 87% amino acid sequence identity to SCD1. RNase protection analysis reveals a 10-fold increase in the expression of SCD2 mRNA during 3T3-L1 preadipocyte differentiation. SCD2 mRNA is expressed constitutively at a high level in brain, is not expressed in liver, and its expression in kidney, adipose, and lung tissue is increased greatly by shifting mice from a diet containing unsaturated fatty acids to a diet devoid of fat. The tissue distribution and the dietary alteration of SCD1 mRNA expression differs markedly from that of SCD2 mRNA being absent from brain, constitutive in adipose tissue, and subject to negative control in liver by feeding a diet containing unsaturated fatty acids. The SCD2 gene spans approximately 15 kilobase pairs and consists of six exons and five introns, with intron/exon junctions similar to those of SCD1. As determined by primer extension analysis the start site of transcription maps 300 nucleotides upstream of the initiator methionine codon. Unlike the SCD1 gene, SCD2 lacks a typical "TATA" box in the 5'-flanking region, but has two "CCAAT" boxes at positions -90 and -135 relative to the transcription initiation site. The SCD2 promoter contains a 140-base pair sequence (located between nucleotides -54 and -201) which possesses 77% sequence identity to a region (located between nucleotides -472 and -325) in the SCD1 promoter. There is a GC-rich sequence in the SCD2 promoter (at nucleotide -175) similar to the binding site for the nuclear transcription factor Sp1 as well as an element with homology to the core consensus sequence for the glucocorticoid regulatory element position -500 and a potential CCAAT box/enhance binding protein sequence at position -540. The SCD gene family provides a new model system for the study of differentiation-induced as well as tissue-specific metabolite controlled gene expression.
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PMID:Differentiation-induced gene expression in 3T3-L1 preadipocytes. A second differentially expressed gene encoding stearoyl-CoA desaturase. 257 68

A segment of 712 bases coding for part of the human stearoyl-CoA desaturase gene was made by polymerase chain reaction (PCR) using primers based on published rat cDNA sequences. The human PCR product was confirmed by DNA sequencing. It was next cloned into a vector from which anti-sense, highly radioactive RNA transcripts were made in vitro using T7 polymerase. The transcripts were used to probe desaturase mRNA in a number of human tumour and control tissues, using a very sensitive solution hybridization/RNase protection assay. Increased desaturase mRNA levels were found in colonic and oesophageal carcinomas and in hepatocellular adenoma; however, no consistent trend was seen in hepatocellular carcinoma. It is suggested that certain classes of tumour may exhibit increased levels of desaturase mRNA.
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PMID:Partial characterization of a cDNA for human stearoyl-CoA desaturase and changes in its mRNA expression in some normal and malignant tissues. 790 40

The effect of vitamin A supplementation on stearoyl-CoA desaturase gene 1 expression in mouse liver was characterized. Normal BALB/c mice were fed 0.01% and 0.1% retinol palmitate as components of nonpurified diets. This treatment resulted in a 3-fold and a 7-fold induction of SCD1 mRNA levels, respectively, as determined by RNase protection analysis. Vitamin A-deficient animals were also fed diets containing 0.01% and 0.1% retinol palmitate, resulting in a similar pattern of SCD1 mRNA induction. Fatty acid synthase and beta-actin mRNA levels did not respond consistently or significantly to retinoic acid treatment. Dietary and hormonal studies were carried out to investigate the role of the retinoid X receptor in the regulation of SCD1 by type II steroid hormones. A receptor-saturating dose of thyroid hormone, triiodothyronine, repressed vitamin A-elevated SCD1 mRNA levels in vivo. Peroxisome proliferator-elevated SCD1 mRNA levels were unaffected by administration of thyroid hormone. This suggests that the retinoic acid receptor transcriptionally regulates SCD1 through a traditional mechanism of heterodimerization with the retinoid X receptor.
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PMID:Regulation of hepatic stearoyl-CoA desaturase gene 1 by vitamin A. 907 Feb 50

Clones corresponding to ovine stearoyl-CoA desaturase (SCD) cDNA were isolated from an adipose tissue cDNA library. All of these clones represented a single mRNA species as judged by restriction fragment and DNA sequence analysis. RNase protection analysis demonstrated that this SCD transcript is highly expressed in adipose tissue and liver, and in the mammary gland of lactating animals. A lower level of expression was detectable in a variety of other tissues including brain. Levels of the SCD transcript were decreased in adipose tissue during lactation, and this appears to be related to a marked decline in serum insulin and insulin-responsiveness of the tissue. Southern analysis of ovine and mouse genomic DNA demonstrated that the ovine SCD cDNA hybridised in a manner consistent with a single gene for SCD in ovine DNA; mouse genomic DNA produced a pattern of hybridisation consistent with the previously characterised mouse SCD-1 and SCD-2 genes. Three ovine cosmids were isolated that comprised the restriction fragments predicted by the genomic Southern analysis. The ovine SCD gene was predicted to be encompassed within a 23 kbp region that was present in all three cosmids. These results demonstrate that SCD is transcribed from a single gene in the ovine genome and this gene is insulin-responsive in ovine adipose tissue.
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PMID:Stearoyl-CoA desaturase mRNA is transcribed from a single gene in the ovine genome. 955 90

Our objectives were 2-fold: to determine the effect of dietary linoleate on milk fat composition and on transcript abundance of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), lipoprotein lipase (LPL), and stearoyl-CoA desaturase (SCD) mRNA in mammary tissue, and to evaluate milk somatic cell mRNA as a source of mammary tissue mRNA for these enzymes. Eighteen primiparous, crossbred beef cows (BW = 411 +/- 24 kg; BCS = 5.25) were offered Foxtail millet hay at 1.68% of BW daily and either a low-fat control (n = 9) or a high-linoleate (79% 18:2n-6), cracked safflower seed supplement (n = 9). Diets were isonitrogenous and isocaloric, and the linoleate diet contained 5.4% of DMI as fat. At slaughter (37 +/- 3 d postpartum), mammary tissue was sampled and immediately frozen in liquid N2 before being stored at -80 degrees C. Milk samples were obtained from the same mammary glands and immediately centrifuged at 1,200 x g to pellet somatic cells. A ribonuclease protection assay was used to quantify the mRNA in the mammary gland and milk somatic cells. Effects of diet, tissue, or their interaction were not observed for ACC (P = 0.28, 0.89, and 0.35, respectively), FAS (P = 0.38, 0.66, and 0.20, respectively), LPL (P = 0.09, 0.15, and 0.43, respectively), or SCD (P = 0.45, 0.19, and 0.29, respectively). Dietary effects on fatty acid profile of the milk fat suggested that linoleate supplementation might have decreased de novo lipogenesis while increasing uptake of dietary fatty acids; this effect was consistent with a trend toward greater LPL mRNA for linoleate-fed cows (P = 0.09). Correlations (r values) between mammary tissue and milk somatic cell data for each mRNA for the low-fat control diet were: ACC, 0.76 (P = 0.02); FAS, 0.69 (P = 0.04); LPL, 0.68 (P = 0.04); and SCD, 0.73 (P = 0.05), and for the linoleate diet were: ACC, 0.85 (P = 0.003); FAS, 0.75 (P = 0.02); LPL, 0.90 (P = 0.001); and SCD, 0.73 (P = 0.03). We conclude that milk somatic cells obtained from lactating beef cows can be used as a source of RNA to study nutritional regulation of mammary gland lipogenesis in cows fed dietary fat supplements.
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PMID:Evaluation of milk somatic cells as a source of mRNA for study of lipogenesis in the mammary gland of lactating beef cows supplemented with dietary high-linoleate safflower seeds. 1690 43