Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have isolated and characterized the gene encoding the bovine endothelin (ET) receptor ETB with seven putative membrane-spanning domains. The gene exists as a single copy of the bovine genome and extends over 36 kilobases. The coding region is divided into seven exons separated by six introns; the first exon encodes the first and second transmembrane domains and each of the following transmembrane domains is encoded by a separate exon. The 5' region of the transcript was examined by the ribonuclease protection analysis; multiple start sites were deduced with no apparent "TATA" box in the expected upstream region. Northern blot analysis demonstrated a widespread but tissue-specific distribution of the ETB receptor in bovine tissues.
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PMID:Structure of the bovine endothelin-B receptor gene and its tissue-specific expression revealed by northern analysis. 128 94

The potent vascular, cardiac, and renal actions of endothelin-1 (ET-1) suggest a role for this vasoconstrictor peptide in the pathophysiology of heart failure (HF). Recent studies have shown increased levels of ET-1 peptide accompanied by increased ETB receptor binding in the left ventricle during experimental HF. However, much less is known about the regulation of mRNA expression of these genes in HF. We compared the levels of mRNA expression for ET-1 and ET receptors (ETA and ETB) in the left ventricle of rats with HF induced by coronary artery ligation (n = 6) vs. sham-operated animals (n = 6). Levels of mRNA for ET-1 were determined by ribonuclease protection assay (RPA) using beta-actin as the internal control, whereas ET receptors were quantified by quantitative-competitive RT-PCR. Compared with sham animals, ET-1, ETA, and ETB receptor mRNA levels were markedly upregulated in the left ventricle by 6.6 +/- 1.8-fold (p < 0.01), 3.2 +/- 0.6-fold (p < 0.05), and 3.5 +/- 1.0-fold (p < 0.05), respectively. ET-1 mRNA levels were measured in two additional groups of rats (HF and sham; n = 6 each) treated for 4 weeks with the selective ETA receptor antagonist LU135252. This treatment had no significant effect on ET-1 mRNA expression in sham animals but reduced the upregulation of ET-1 expression in the HF group by 41 +/- 19% (p < 0.05). This study confirms the potential importance of ET-1 in HF and suggests that increased expression of ET-1 and ET receptors in the failing ventricle may contribute to alteration in basal cardiac contractility and myocardial remodeling.
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PMID:Coordinated upregulation of the cardiac endothelin system in a rat model of heart failure. 959 63

Endothelin-1 (ET-1) and nitric oxide (NO) are potent vasoactive factors known to play a role in vascular remodeling. This study assessed the temporal expression of endothelial NO synthase (eNOS), preproET-1, and ETA and ETB receptor mRNAs in the rat carotid artery after balloon injury using quantitative competitive reverse transcription-polymerase chain reaction (qcRT-PCR) and the ribonuclease protection assay (RPA). Levels of ET-1 increased sharply after arterial injury, peaking (5.1-fold) at 2 days. This was associated with a dramatic increase in the expression of ETB (63-fold) and ETA (158-fold) receptor mRNA, peaking at days 1 and 2, respectively. Expression of eNOS was not detectable immediately after balloon injury, consistent with complete denudation, but reappeared after day 2 and increased to preinjury levels by day 14. The recovery of eNOS expression mirrored the return of ET-1 and ET receptor expression to baseline levels. The results confirm profound upregulation of the ET system in this model of arterial injury and suggest a critical role for eNOS expression and re-endothelialization in the normalization of ET-1 and ET receptor expression during the recovery phase, events that may be important in long-term arterial patency.
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PMID:Expression of endothelial factors after arterial injury in the rat. 959 71