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)

The plasma cholesteryl ester transfer protein (CETP) is known to facilitate the transfer of lipids between plasma lipoproteins. The human CETP gene is a complex locus encompassing 16 exons. The CETP mRNA is found in liver and small intestine as well as in a variety of peripheral tissues. While the CETP cDNA from human adipose tissue was being cloned, a variant CETP cDNA was discovered which excluded the complete sequence encoded by exon 9, but which was otherwise identical to the full-length CETP cDNA, suggesting modification of the CETP gene transcript by an alternative RNA splicing mechanism. RNase protection analysis of tissue RNA confirmed the presence of exon 9 deleted transcripts and showed that they represented a variable proportion of the total CETP mRNA in various human tissues including adipose tissue (25%), liver (33%), and spleen (46%). Transient expression of the exon 9 deleted cDNA in COS cells or stable expression in CHO cells showed that the protein encoded by the alternatively spliced transcript was inactive in neutral lipid transfer, smaller, and poorly secreted compared to the protein derived from the full-length cDNA. Endo H digestion suggested that the inactive, cell-associated protein was present within the endoplasmic reticulum. The experiments show that the expression of the human CETP gene is modified by alternative splicing of the ninth exon, in a tissue-specific fashion. The function of alternative splicing is unknown but could serve to produce a protein with a function other than plasma neutral lipid transfer, or as an on-off switch to regulate the local concentration of biologically active protein.
 ...
PMID:Alternative splicing of the mRNA encoding the human cholesteryl ester transfer protein. 154 May 91

Cholesteryl ester transfer activity is increased in plasma of cholesterol-fed rabbits. To investigate the mechanisms leading to changes in activity, we measured cholesteryl ester transfer protein (CETP) mass by RIA and CETP mRNA abundance by Northern and slot blot analysis using a human CETP cDNA probe in control (n = 8) and cholesterol-fed rabbits (n = 10). Cholesterol feeding (chow plus 0.5% cholesterol, 10% corn oil) for 30 d increased CETP mass in plasma 3.2-fold in the cholesterol-fed rabbits (12.45 +/- 0.82 micrograms/ml) compared with controls (3.86 +/- 0.38 micrograms/ml). In the hypercholesterolemic rabbit, liver CETP mRNA levels were increased 2.8 times control mRNA levels. Actin, apo E, lecithin-cholesterol acyltransferase, and albumin mRNA abundances were unchanged. In contrast to the widespread tissue distribution in humans, CETP mRNA was not detected in extrahepatic tissues of either control or cholesterol-fed animals. Using a sensitive RNase protection assay, the increase in liver CETP mRNA was detectable within 3 d of beginning the high cholesterol diet. Thus, in response to the atherogenic diet there is an early increase in liver CETP mRNA, probably causing increased CETP synthesis and secretion, and increased plasma CETP. The results indicate that the CETP gene may be regulated by diet-induced changes in lipid metabolism.
 ...
PMID:Atherogenic diet increases cholesteryl ester transfer protein messenger RNA levels in rabbit liver. 229 10

Cholesteryl ester transfer protein (CETP) has a well-defined role in plasma neutral lipid transport. CETP synthesized by human adipose tissue may contribute to the plasma CETP pool. CETP mRNA abundance increases in subcutaneous adipose tissue in response to cholesterol feeding and we have hypothesized that CETP gene expression is regulated by a specific pool of cellular sterol. In the present study, we have quantified CETP mRNA levels in subcutaneous adipose tissue of 10 female subjects using a solution hybridization RNase protection assay. Particulate (membrane cholesterol) and lipid droplet cholesterol (core cholesterol) were determined by gas chromatography. CETP mRNA abundance in these adipose tissue specimens correlated significantly with membrane cholesterol expressed as a fraction of membrane protein (r = 0.67, P = 0.031). There was also a linear relationship between CETP mRNA abundance and membrane cholesterol to core triglyceride ratio (r = 0.77, P = 0.009) and a strong correlation between the percentage of cellular cholesterol in the membrane fraction (ratio of membrane to core cholesterol) and CETP mRNA abundance (r = 0.91, P = 0.0002). In contrast, there was a negative relationship between each of lipid droplet cholesterol and triglyceride and CETP mRNA levels. Human adipose tissue maintained in organ culture for several days was shown to secrete CETP into the culture medium. Incubation with cholesterol-rich chylomicron remnants elicited a dose-dependent increase in both membrane and core cholesterol and a concomitant increase in the level of CETP mRNA. These studies demonstrate that adipose tissue CETP mRNA abundance is a function of membrane cholesterol concentration rather than lipid droplet cholesterol and that CETP mRNA increases with adipocyte cholesterol enrichment via chylomicron remnants. CETP gene expression is highest in small lipid-poor adipocytes, suggesting that CETP synthesized and secreted by adipocytes may have a role in promoting cellular cholesterol accumulation.
 ...
PMID:Cholesteryl ester transfer protein (CETP) mRNA abundance in human adipose tissue: relationship to cell size and membrane cholesterol content. 884 81

Cholesteryl ester transfer protein (CETP) plays a pivotal role in the reverse transport of cholesterol and in the remodeling of circulating lipoproteins. While plasma and adipose tissue levels of CETP are affected by a variety of metabolic conditions, the extent of the effects of dietary factors, other than high cholesterol feeding, are not well understood. To further explore this paradigm, male Golden Syrian hamsters were fed for 4 weeks with a 60%-enriched fructose diet (F) and were compared to a matched group of animals fed with a normal chow diet (N). After feeding for 4 weeks, plasma insulin concentrations were lower in animals fed fructose than in control animals (F: 3.3+/-0.8 vs N: 7.4+/-1.9 ng/mL; p<0.03), but there was no significant difference in plasma glucose concentrations between the two groups (F: 138+/-7 vs N: 148+/-10 mg/dL; p>0.05). Fructose-fed animals showed significant increases in plasma triglyceride (F: 269+/-22 vs N: 165+/-22 mg/dL; p<0.01) and plasma cholesterol (F: 150+/-10 vs N: 113+/-6 mg/dL; p<0.02) concentrations compared with control animals. Total CETP activity and immunoreactive mass were higher in the plasma of fructose-fed animals that in that of controls (F: 1036+/-70 vs N: 826+/-43 pmol/h/mL, p<0.04 and F: 24.5+/-3.1 vs N: 37.5+/-4.3 AU, p<0.02, respectively). Adipose tissue CETP mRNA levels, assessed by the very sensitive ribonuclease protection assay, were 53% higher in fructose-fed animals than in controls (F: 14.1+/-2.0 vs N: 9.2+/-1.0 AU over a rRNA control; p<0.04). Adipose tissue CETP activity and immunoreactive mass also showed a statistically significant increase in the fructose-fed hamsters compared with those fed a normal diet (p<0.04). In conclusion, fructose feeding in Syrian hamsters induces a mixed dyslipidemia. These metabolic changes are accompanied by a significant increase in CETP levels, both in plasma and in adipose tissue. This phenomenon suggests that the increase in the expression of adipose tissue CETP may be caused either by the ambient hypercholesterolemia resulting from fructose feeding or by an attenuation of a possible inhibitory effect of plasma insulin concentrations on the expression of adipose tissue CETP in this feeding paradigm.
 ...
PMID:Induction of cholesteryl ester transfer protein in adipose tissue and plasma of the fructose-fed hamster. 1147 89

The intercellular washing fluid (IWF) of Malus domestica cv. Holsteiner Cox before and after application of the non-pathogenic bacterium Pseudomonas fluorescens Bk3 to the leaves was investigated in a comparative manner. SDS-PAGE in combination with ESI Q-ToF mass spectrometry, and homology search in relevant data bases revealed the highly up-regulated expression of several pathogenesis-related plant proteins in the apoplast of the leaves treated with P. fluorescens. These proteins were beta3-1,3-glucanase, chitinase, thaumatin-like protein, ribonuclease-like protein, and a hevein-like protein. Moreover, a 9 kDa non-specific lipid transfer protein was significantly reduced after the application of P. fluorescens. The possible relevance of a pre-treatment of apple cultivars with the non-pathogenic bacterium P. fluorescens Bk3, as an alternative method to the treatment with fungicides, for increasing the resistance of susceptible apple cultivars against an infection with the fungus Venturia inaequalis is discussed.
 ...
PMID:Up-regulation of pathogenesis-related proteins in the apoplast of Malus domestica after application of a non-pathogenic bacterium. 1566 44