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)

The biosynthesis of peptides requires the synthesis of the prohormone, several biosynthetic processing enzymes, and other granule constituents. We have investigated the regulated expression of proopiomelanocortin (POMC) and five enzymes essential for the processing of POMC to smaller, bioactive peptides in intermediate pituitary melanotropes. Rats were treated with a dopaminergic agonist (bromocriptine) or antagonist (haloperidol) for periods ranging from 1 h to 5 days, followed by analyses of mRNA levels and protein biosynthetic rates. Multiplex RNase protection assays showed that bromocriptine treatment caused a striking decrease in POMC mRNA levels, and significant decreases in mRNA levels for prohormone convertase 2 (PC2), carboxypeptidase H (CPH), and peptidylglycine alpha-amidating monooxygenase (PAM). Smaller increases in mRNA levels were seen after haloperidol stimulation. Protein biosynthetic rates changed more profoundly than mRNA levels at short drug treatment times, indicating a role for translational effects after treatment with bromocriptine and with haloperidol. The homogeneous population of melanotropes in the intermediate lobe of the pituitary allows a quantitative analysis of transcript levels and biosynthetic rates. POMC mRNA levels are 200-1,000-fold higher than levels of any of the processing enzyme mRNAs, and POMC biosynthetic rates exceed those of PC2, PC1, and PAM by 1,000-10,000-fold.
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PMID:Dopaminergic regulation of secretory granule-associated proteins in rat intermediate pituitary. 866 96

We have chosen a vertebrate model accessible during neurulation, the chick, for analysis of endogenous insulin signaling and its contribution to early embryonic cell survival. Unlike rodents, humans and chickens have a single preproinsulin gene, facilitating its prepancreatic expression characterization. We show that in vivo interference with embryonic insulin signaling using antisense oligonucleotides against the insulin receptor increases apoptosis during neurulation. In contrast, high glucose administration does not increase the level of apoptosis in culture or in vivo. Exogenous insulin and, remarkably, proinsulin achieve similar survival protective effects at 10(-8) mol/l. The low abundant preproinsulin mRNA from the prepancreatic embryo is translated to a protein that remains as unprocessed proinsulin. This concurs with the absence of prohormone convertase 2 (PC2) in the embryo, whereas PC2 is present later in embryonic pancreas. A C-peptide--specific antibody stains proinsulin-containing neuroepithelial cells of the chick embryo in early neurulation, as well as other cells in mesoderm- and endoderm-derived structures in the 2.5-day embryo. We have determined by 5'-RACE (rapid amplification of cDNA ends), and confirmed by RNase protection assay, that prepancreatic and pancreatic proinsulin mRNA differ in their first exon, suggesting differential transcriptional regulation. All these data support the role of endogenous proinsulin in cell survival in the chick embryo during important pathophysiologic periods of early development.
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PMID:Unprocessed proinsulin promotes cell survival during neurulation in the chick embryo. 1187 78