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

RNA was extracted from the pancreatic islets of channel catfish in the presence of the ribonuclease inhibitor, diethyl pyrocarbonate (oxydiformate). High molecular weight RNA was observed on sucrose gradient analysis. enrichment of mRNA was achieved by oligo(2'-deoxythymidylic acid)-cellulose affinity chromatography. The mRNA fraction stimulated incorporation of [35S]methionine into protein up to 30-times the background in the wheat-germ cell-free system. Analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed two major proteins corresponding to molecular weights of 27 000 and 11 000. These proteins were not observed in the absence of mRNA or in the presence of mRNAs from other tissues. They were also synthesized in the ascites tumour cell-free system. No protein co-migrating with proinsulin or insulin was detected in either the ascites or wheat-germ cell-free systems. Pancreatic islet slices also synthesized the proteins of 27 000 and 11 000 molecular weight and smaller ones as well.
 ...
PMID:Isolation of a biologically active messenger RNA: preparation from fish pancreatic islets by oligo(2'-deoxythymidylic acid) affinity chromatography. 78 80

Interactions of several proteins with glutathione-insulin transhydrogenase (GIT) have been investigated by determining their ability to inhibit degradation of 125I-labeled insulin catalyzed by GIT. The inhibition by every insulin analog (des-Asn-des-Ala-pork insulin, desoctapeptide-pork insulin, des-Ala-pork insulin, pork insulin, proinsulin, and guinea pig insulin) was competitive vs. competitive vs. insulin indicating that they function as alternate substrates. The insulin analogs with the least hormonal activity showed the highest potency as inhigitors of insulin degradation. Whereas native ribonuclease and lysozyme showed little or no inhibition, their scrambled forms (i.e. reduced and randomly reoxidized) showed competitive inhibition with a potency greater than that of insulin. These results suggest that the conformation of the substrate or inhibitor is probably the major factor in determining the specificity for (or binding to) the enzyme. Studies withother peptide hormones showed competitive inhibition with vasopressin and oxytocin and noncompetitive inhibition with glycagon. The inhibition with growth hormone could be either competitive or noncompetitive. The inhibition by glucagon and growth hormone (physiologic antagonists of insulin) could serve as a control mechanism to modulate the activity of enzyme. The following showed very little or no inhibition; the native and scrambled form of pepsinogen, trypsin inhibitor of beef pancreas and of lima bean, C-peptide of pork proinsulin, and heptapeptide (B23-B29) of insulin.
 ...
PMID:Interaction of insulin analogs, glucagon, growth hormone, vasopressin, oxytocin, and scrambled forms of ribonuclease and lysozyme with glytathione-insulin transhydrogenase (thiol: protein-disulfide oxidoreductase): dependence upon conformation. 117 Aug 77

Although the formation of native disulfide bonds of a protein from randomly linked disulfides by protein disulfide isomerase has been extensively studied, the possibility of simultaneous formation of the native proteins from a mixture has not been examined. It is shown in this paper that native ribonuclease and proinsulin can be nearly quantitatively formed by protein disulfide isomerase from a mixture of their S-sulfonated derivatives independent of the presence of each other.
 ...
PMID:Simultaneous formation of native ribonuclease and proinsulin from their mixed S-sulfonated derivatives by protein disulfide isomerase. 148 88

Mice and rats express two nonidentical insulins from a pair of unlinked genes. We have applied a nuclease protection assay, which can sensitively quantify each of the mouse insulin mRNAs, to the resolution of the following questions concerning their expression. First, it has not been established whether alterations in expression of one or both of these genes cause differing total insulin biosynthetic capacity noted between several inbred mouse strains. These studies showed that the relative abundance of mRNAs encoding mouse insulins I and II was identical in four separate mouse strains. In spontaneously obese, hyperinsulinemic (db/db)C57BL/KsJ mice, both proinsulin I and proinsulin II mRNAs were increased relative to the levels in normal (+/db) C57BL/KsJ mice, but again the ratio of the two mRNAs did not differ. The ratio was nearly identical to that for the orthologous mRNAs in rats, indicating that the mechanisms which regulate insulin mRNAs in rodents are conserved in both genes in several mouse strains and between rodent species. This finding suggests that differences between mouse strains in insulin biosynthetic capacity result from differences in the glucose sensing/signalling mechanism at a point before coordinate gene transcription. Second, low levels of insulin synthesis have been suggested as an explanation for relatively high levels of insulin in several nonpancreatic tissues. We showed that the ribonuclease protection assay, sufficiently sensitive to measure 1/2000th the amount of insulin mRNA present in pancreas, was unable to detect insulin mRNA in salivary gland. This result indicates that the high levels of radioimmunoassayable insulin detected in salivary glands are not the result of insulin synthesis in situ.
 ...
PMID:Proinsulin I and II gene expression in inbred mouse strains. 260 62

A method is described for separation of polyribosomes from as few as 25 isolated Islets of Langerhans, representing about 250 mug of pancreatic tissue. Islets are labeled with [(3)H]leucine and polysomes are isolated with liver polyribosomes, which serve as carrier and inhibitor of ribonuclease activity. Islets incubated at 37 degrees C for 45 min in 15.5 mM glucose, then pulsed with [(3)H]leucine, incorporated about 2-3 times more label into nascent peptides on islet polysomes than islets incubated in 2.8 mM glucose. Sucrose gradient analysis of the labeled polysomes indicated that raising the glucose concentration preferentially stimulated synthesis of peptides on trisomes and larger polyribosomes. Islets incubated with [(3)H]leucine for 15 min incorporated two-thirds of the label into proteins on membrane-bound polysomes. At least 85% of the proinsulin synthesis during this time occurs on membrane-bound polysomes.
 ...
PMID:Insulin biosynthesis: studies of Islet polyribosomes (nascent peptides-sucrose gradient analysis-gel filtration). 455 Nov 47

Previous studies have shown that a neutral metallo-endopeptidase purified from rat kidney degrades the B chain of insulin, glucagon, ACTH and, at a markedly slower rate, the A chain of insulin. In contrast the enzyme does not attack native insulin, oxytocin, vasopressin, ribonuclease, albumin or denatured hemoglobin. The current studies demonstrate that the neutral peptidase also degrades the isolated C-peptide of proinsulin and cleaves certain peptide bonds in and near the C-peptide moiety of native proinsulin. Time courses of the formation of fluorescamine-reactive material during digestion of proinsulin and isolated C-peptide with the peptidase were identical. However, structural analysis of the peptidase-digested proinsulin showed that the enzyme does not convert proinsulin to insulin but that the peptidase cleaves one bond, Tyr26-Thr27, in the B chain moiety and five bonds in the C-peptide moiety, producing four split proinsulins. One of the split proinsulins is des-octacosa-peptide (27-54) porcine proinsulin or des-tetracosapeptide (27-50) bovine proinsulin. Each is a derivative of the insulin molecule having an extension of nine residues (ten residues in the case of the derivative from bovine proinsulin) at the N-terminus of A chain and lacking four residues at the C-terminus of B chain. This two chain derivative retains full immunoreactivity with insulin antibodies and exhibits 2.4-times more biological activity (promotion of glycogenesis in primary cultured hepatocytes) than proinsulin and about two-thirds the activity of insulin.
 ...
PMID:Degradation of proinsulin and isolated C-peptide by rat kidney neutral metallo-endopeptidase. 702 23

Insulin-like growth factors (IGFs) I and II are two single-chain polypeptide hormones that are structurally related to each other and to proinsulin. Among the large number of growth factors involved in ovarian physiology, IGF-I and IGF-II are considered to be important progression factors for ovarian follicular development. To explore the ovarian expression of IGF-I, IGF-II and their receptor genes, a solution hybridization/RNase protection assay, was used. IGF-I mRNA was seen in the granulosa cells, and IGF-II mRNA in the theca-interstitial compartment. To study the hormonal regulation of the IGF-I and IGF-II gene, immature (21-day-old) hypohysectomized rats were treated with FSH (10 micrograms/day), GH (150 micrograms/day) and diethylstilbestrol (DES subcutaneous implant/5 days). Estrogen differentially regulated ovarian IGF-I and IGF-II gene expression. In concert with GH, estrogen up-regulated ovarian IGF-I mRNA, but significantly decreased hepatic IGF-I gene expression. Both IGF receptors (type I and type II) as well as the insulin receptor gene, were expressed in both ovarian cells. The expression of the type I IGF receptor gene (but not the type II IGF gene) was up-regulated by FSH and estrogen in vivo. In conclusion, these studies may serve to better understand the auto paracrine role of IGF, and their receptors in the pathophysiology of follicle recruitment, oocyte maturation and potentially embryo development.
 ...
PMID:Regulation of the genes for insulin-like growth factor (IGF) I and II and their receptors by steroids and gonadotropins in the ovary. 762 58

Olfactory receptors constitute the largest family among G protein-coupled receptors, with up to 1000 members expected. We have previously shown that genes belonging to this family were expressed in the male germ line from both dog and human. We have subsequently demonstrated the presence of one of the corresponding olfactory receptor proteins during dog spermatogenesis and in mature sperm cells. In this study, we investigated whether the unexpected pattern of expression of olfactory receptors in the male germ line was conserved in other mammalian species. Using reverse transcription-PCR with primers specific for the olfactory receptor gene family, about 20 olfactory receptor cDNA fragments were cloned from the testis of each mammalian species tested. As a whole, they displayed no sequence specificity compared to other olfactory receptors, but highly homologous, possibly orthologous, genes were amplified from different species. Finally, their pattern of expression, as determined by RNase protection assay, revealed that many but not all of these receptors were expressed predominantly in testis. The male germ line from each mammalian species tested ins thus characterized by a specific repertoire of olfactory receptors, which display a pattern of expression suggestive of their potential implication in the control of sperm maturation, migration, or fertilization.
 ...
PMID:Specific repertoire of olfactory receptor genes in the male germ cells of several mammalian species. 911 60

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.
 ...
PMID:Unprocessed proinsulin promotes cell survival during neurulation in the chick embryo. 1187 78

Cpf1, an RNA-guided DNA endonuclease that belongs to a new class II CRISPR system, has recently been harnessed for genome editing. Herein, we report an RNase-resistant caged truncated pre-tRNA-like crRNA (catRNA) that confers precise and efficient gene editing with the Lachnospiraceae bacterium Cpf1 (LbCpf1) and enables the reprogramming of catalytically dead LbCpf1 (dCpf1) lacking DNA endonuclease activity into a transcriptional modulator. Specific gene knock-outs and knock-ins were increased 3.2-fold and 4.3-fold, respectively, with catRNA compared to that induced by conventional crRNA. A much higher augmentation of gene disruption (up to 37-fold) was observed when electroporation was used. We report herein that catRNA enables efficient gene activation with dCpf1 activators. Our study reveals the potential of catRNA and a versatile application of the CRISPR/Cpf1 system, establishing a simple approach for selective gene perturbation in mammalian cells.
 ...
PMID:Genetic editing and interrogation with Cpf1 and caged truncated pre-tRNA-like crRNA in mammalian cells. 3000 72


1