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 beta 3-adrenoceptor is a G protein-coupled receptor which mediates metabolic functions of the endogenous catecholamines epinephrine and norepinephrine. Questions exist regarding distribution of the beta 3-adrenoceptor in human tissue. In order to examine the distribution of beta 3-adrenoceptor mRNA in human tissues, we used sensitive and specific RNase protection assays without previous PCR amplification in an extensive list of human tissues. We confirm the presence of beta 3-adrenoceptor mRNA in human white fat from several locations, gall bladder, and small intestine, as well as extend the distribution of beta 3-adrenoceptor mRNA to previously uncharacterized human tissues such as stomach and prostate. The presence of beta 3-adrenoceptor mRNA in human white adipose tissue has important implications regarding possible use of beta 3-adrenoceptor selective agonists as anti-obesity agents, and the demonstration of beta 3-adrenoceptor mRNA in a number of gastrointestinal tissues and prostate raises the question of the role of the beta 3-adrenoceptor in motility and secretory processes.
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PMID:Distribution of beta 3-adrenoceptor mRNA in human tissues. 762 95

The gene encoding the rat V1a arginine vasopressin (AVP) receptor was isolated, and its structural organization and 5'-flanking region were characterized. In addition, the complete cDNA sequence of the major transcript of the rat V1a receptor gene was determined. Southern blots demonstrated a single copy of the V1a receptor gene in the rat genome, spanning a region of 3.8 kilobases (kb) and consisting of two exons and one intron (1.8 kb). The location of the intron was unique among G protein-coupled receptor genes in that the first exon encodes six of the seven transmembrane regions, the seventh region being encoded by the second exon. Primer extension, RNase protection, and rapid amplification of the 5'-end of the cDNA identified three transcriptional initiation sites (-405, -243, and -237), the major transcription initiation sites being mapped to positions -243 and -237 base pairs (bp) upstream of the ATG initiation codon (+1 bp). This portion of the 5'-flanking region has neither a TATA nor a CCAAT box, is GC-rich but has no GC box motif, and has features of promoters seen in housekeeping genes. Chimeras containing 2.2 kb of the 5'-flanking region and deletion analyses using the chloramphenicol acetyltransferase gene indicated that a "minimal" region, exhibiting promoter activity and tissue specificity, is located between nucleotides -296 and -221, when transfected into vascular smooth muscle cells. Gel mobility shift assay and Southwestern blotting suggested that approximately 30- and approximately 28-kDa nuclear proteins specifically bind to this region. Rapid amplification of the 3'-end of the cDNA showed that the major transcript terminates 442 bp downstream of the stop codon, in agreement with the mRNA size (2.1 kb). This study demonstrated a distinctive feature in the structural organization of the AVP-oxytocin receptor family genes, and characterization of the 5'-flanking region reported here will lead to a better understanding of the mechanism of transcriptional regulation of the rat V1a AVP receptor gene.
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PMID:Structure of the rat V1a vasopressin receptor gene and characterization of its promoter region and complete cDNA sequence of the 3'-end. 765 21

We have used a homology based approach to identify G protein-coupled receptors preferentially expressed in retinal and taste cells. Rat and bovine sequences encoding a novel G protein-coupled receptor have been isolated. Analysis indicates that while the protein sequence is most similar to the receptors for somatostatin and opiates, it is unlikely to be a subtype of these receptors. Northern and RNase protection analysis indicates that the gene is preferentially expressed in neural and sensory tissues.
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PMID:A novel putative neuropeptide receptor expressed in neural tissue, including sensory epithelia. 773 47

The GnRH receptor (GnRH-R) is a cell surface, G protein-coupled receptor that is highly expressed in pituitary gonadotropes. Activation of the receptor by GnRH stimulates the release of FSH and LH. Pituitary GnRH-R numbers and, hence, gonadotrope responsiveness to GnRH vary under different conditions and are regulated to a large extent by GnRH itself. To study the transcriptional regulation of the GnRH-R gene, a genomic clone containing 1.2 kilobases (kb) of the 5'-flanking region of mouse GnRH-R gene was isolated and characterized. A major transcriptional start site was identified 62 nucleotides upstream of the translational start site by primer extension and ribonuclease protection analyses. The promoter region does not contain canonical TATA sequences in the appropriate location. To determine whether this putative promoter is functional, it was subcloned into a luciferase reporter plasmid (GnRH-RLuc), and its transient expression was studied in cell lines of gonadotrope (alpha T3-1) and somatolactotrope (GH3) origins as well as those of nonpituitary origin (JEG-3 and CV-1). Luciferase activity was increased in alpha T3-1 (246-fold +/- 34.5-fold; P < 0.005) compared with the promoterless vector control but was considerably lower in GH3 (41-fold +/- 3.9-fold; P < 0.005), JEG-3 (12-fold +/- 0.9-fold; P < 0.005) and CV-1 (8-fold +/- 1.3-fold) indicating that GnRH-RLuc is preferentially expressed in cells of gonadotrope origin. Furthermore, GnRH agonist stimulated luciferase activity 3.4-fold +/- 0.3-fold (P < 0.005) above basal levels in GH3 cells cotransfected with rat GnRH-R complementary DNA, indicating that the GnRH-R promoter sequence is responsive to this ligand. In summary, we have identified and partially characterized the promoter region of the mouse GnRH-R and demonstrated that the regulatory elements for tissue-specific expression as well as for GnRH regulation are present within a 1.2-kb 5'-flanking region of the mouse GnRH-R gene.
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PMID:Isolation and characterization of the 5'-flanking region of the mouse gonadotropin-releasing hormone receptor gene. 798 11

The beta-adrenergic receptor kinase (beta ARK) specifically phosphorylates the agonist-occupied forms of the beta 2-adrenergic receptor and related G protein-coupled receptors. beta ARK is one of the best characterized members of a growing family of G protein-coupled receptor kinases. In this article we report the isolation and structural organization of the human beta ARK gene. The gene spans approximately 23 kilobases and is composed of 21 exons interrupted by 20 introns. Exon sizes range from 52 bases (exon 7) to over 1200 bases (exon 21), intron sizes from 68 bases (intron L) to 10.8 kilobases (intron A). The splice sites for donor and acceptor were in agreement with the canonical GT/AG rule. Functional regions of beta ARK are described with respect to their location within the exon-intron organization of the gene. Primer extension and RNase protection assays suggest a major transcription start site approximately 246 bases upstream of the start ATG. Sequence analysis of the 5'-flanking/promoter region reveals many features characteristic of mammalian housekeeping genes, i.e. the lack of a TATA box, an absent or nonstandard positioned CAAT box, high GC content, and the presence of Sp1-binding sites. The extraordinarily high GC content of the 5'-flanking region (> 80%) helps define this region as a CpG island that may be a principal regulator of beta ARK expression.
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PMID:Structure of the human gene encoding the beta-adrenergic receptor kinase. 819 24

The principal mechanism of homologous desensitization of the beta-adrenergic receptor (beta2AR) is phosphorylation of the receptor by the betaAR kinase (betaARK) or other closely related G protein-coupled receptor kinases (GRKs). However, within a single organ such as the lung where many cell types express the receptor, the presence or extent of beta2AR desensitization in different cells has been noted to be highly variable. We hypothesized that such variability in desensitization is due to significant cell-type differences in betaARK expression and/or function. To approach this, in situ hybridization was carried out in the lung and indeed revealed heterogeneity in betaARK gene expression. Quantitative studies using ribonuclease protection assays with cell lines revealed that the level of betaARK mRNA in airway smooth muscle cells was approximately 20% of that in bronchial epithelial cells and approximately 11% of that in mast cells (6.65 +/- 0.96 versus 32.6 +/- 4.0 and 60.7 +/- 1.5 relative units, respectively, p < 0. 001). betaARK2 gene expression was not detected in any of these cells. At the protein level, betaARK expression in airway smooth muscle cells was nearly undetectable, being approximately 10-fold less than that expressed on mast cells. The activities of the GRKs in cell extracts were assessed in vitro by quantitating their ability to phosphorylate rhodopsin in the presence of light. Consistent with the gene and protein expression results, a marked discrepancy in activities was observed between extracts derived from mast cells (90.7 +/- 0.5 relative units) as compared to airway smooth muscle cells (9.28 +/- 0.6 relative units, p < 0.001). In contrast, the activities of protein kinase A (the other kinase that phosphorylates beta2AR) in these extracts were not different. We predicted, then, that airway smooth muscle beta2AR would undergo minimal short-term (5 min) agonist-promoted desensitization as compared to the beta2AR expressed on mast cells. Mast cell cAMP reached maximal levels after 90 s and did not further increase over time, indicative of receptor desensitization in this cell. In contrast, cAMP levels of airway smooth muscle cells did not plateau, increasing at a rate of 103 +/- 9% per min, consistent with little desensitization over the study period. We conclude that there is significant cell-type variation in expression of betaARK and that such variation is directly related to the extent of short-term agonist-promoted desensitization of the beta2AR.
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PMID:Heterogeneity in beta-adrenergic receptor kinase expression in the lung accounts for cell-specific desensitization of the beta2-adrenergic receptor. 905 32

The luteinizing hormone receptor (LHR) is a member of the subfamily of glycoprotein hormone receptors within the superfamily of G protein-coupled receptor (GPCR)/seven-transmembrane domain receptors. Over the past eight years, major advances have been made in determining the structure and function of the LHR and its gene. The hormone-binding domain has been localized to exons 1-7 in the extracellular (EC) domain/region of the receptor, which contains several leucine-rich repeats. High-affinity binding of LH and human chorionic gonadotrophin (hCG) causes secondary hormone or receptor contacts to be established with regions of the EC loop/transmembrane module that initiate signal transduction. Models of hormone-receptor interaction have been derived from the crystal structures of hCG and of the ribonuclease inhibitor, which also contains leucine-rich repeats. Such models provide a framework for the interpretation of mutational studies and for further experiments. The extracellular domain of the receptor has been overexpressed in vitro, which will facilitate crystallographic resolution of the structure of the receptor-binding site. The transmembrane domain/loop/cytoplasmic module transduces the signal for coupling to G proteins. Several constitutive, activating mutations that cause human disease have been found in helix VI and adjacent structures. These mutations have provided valuable information about mechanisms of signal transfer and G protein coupling. The structure of the LHR gene has been elucidated, and the regulation of its transcription is beginning to be understood. Valuable insights into receptor evolution have been derived from analysis of sequence homologies, the gene structure of glycoprotein hormone receptors and other members of the GPCR family, and the glycoprotein hormone receptor-like precursors identified in several invertebrate species.
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PMID:The luteinizing hormone receptor. 955 73

The murine gastrin-releasing peptide receptor (mGRP-R) is a member of the G protein-coupled receptor family and mediates important physiological actions of its specific ligand, the gastrointestinal hormone/neurotransmitter GRP, including mitogenic properties in the mouse Swiss 3T3 fibroblasts. Glucocorticoids and increases in intracellular cAMP are reported to alter GRP-R gene transcription, but the molecular basis for these effects is unknown. To begin to identify possible gene regulatory mechanisms that are responsible for modifying mGRP-R expression, we determined its structure and investigated its basal promoter activity. We isolated and characterized genomic bacteriophage P1 clones encoding the mouse gastrin-releasing peptide receptor (mGRP-R). By DNA sequencing and Southern blot analyses, we determined the protein coding region to be contained in three exons interrupted by two introns 20 and 2kb in length. The open reading frame of the putative GRP-R gene encodes for a 384-amino-acid protein which demonstrates 48% identity with the mouse BRS-3 protein and 53% identity with the mouse NMB-R protein. The mGRP-R gene locus extends over 29kb and was mapped to the X-chromosome (DXMit20) utilizing a minisatellite polymorphism in the 5' UTR and by fluorescent in-situ hybridization (FISH). In Swiss 3T3 cells, which natively express mGRP-R, two gene-specific mRNA species of 3 and 7kb can be detected by Northern blot analysis. With RNase protection assays, and independently with inverse PCR of 5' RACE clones, common mRNA initiation sites were identified clustered between 21 and 61bp downstream of a TTTAAA motif, which is located 450bp upstream of the ATG translation start site. However, different polyadenylation sites are utilized. A 2kb genomic DNA fragment extending from 2147 to 141 bases 5' to the ATG translation start was cloned into a luciferase reporter plasmid and shown to contain promoter activity in Swiss 3T3 and COS-7 cells. Progressive promoter truncations and mutations of a cyclic AMP response element (CRE) located 83bp upstream of the TTTAAA motif demonstrate that transcriptional mGRP-R activation in Swiss 3T3 cells only occurs when both the TTTAAA motif and the intact CRE site are retained. With the availability of the full structure of the mGRP-R gene and the minimal promoter sequences reported in this study, it will be possible in future studies to investigate the molecular basis for transcriptional regulation of the mGRP-R gene by glucocorticoids, cAMP and other factors.
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PMID:Molecular organization of the mouse gastrin-releasing peptide receptor gene and its promoter. 1068 96

NK cells respond to various chemokines, suggesting that they express receptors for these chemokines. In this paper, we show that IL-2-activated NK (IANK) cells express CC chemokine receptor 4 (CCR4) and CCR8, as determined by flow cytometric, immunoblot, and RNase protection assays. Macrophage-derived chemokine (MDC), the ligand for CCR4, induces the phosphorylation of CCR4 within 0.5 min of activating IANK cells with this ligand. This is corroborated with the recruitment of G protein-coupled receptor kinases 2 and 3 and their association with CCR4 in IANK cell membranes. Also, CCR4 is internalized between 5 and 45 min but reappears in the membranes after 60 min of stimulation with MDC. MDC, thymus and activation-regulated chemokine (TARC), and I-309 induce the chemotaxis of IANK cells, an activity that is inhibited upon pretreatment of these cells with pertussis toxin, suggesting that receptors for these chemokines are coupled to pertussis toxin-sensitive G proteins. In the calcium release assay, cross-desensitization experiments showed that TARC completely desensitizes the calcium flux response induced by MDC or I-309, whereas both MDC and I-309 partially desensitize the calcium flux response induced by TARC. These results suggest that TARC utilizes CCR4 and CCR8. Our results are the first to show that IL-2-activated NK cells express CCR4 and CCR8, suggesting that these receptors are not exclusive for Th2 cells.
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PMID:Human NK cells express CC chemokine receptors 4 and 8 and respond to thymus and activation-regulated chemokine, macrophage-derived chemokine, and I-309. 1075 97

1. Lipoxin (LX) A(4) and aspirin-triggered-LX (ATL) are endogenous lipid-derived mediators that regulate leukocyte trafficking via specific LXA(4) receptors (ALX), and are involved in endogenous anti-inflammation and resolution. Both LXA(4) and ATL are produced by rat tissues in vitro as well as in vivo. In rats, LXA(4) and ATL exhibit potent physiological and pathophysiological roles. Thus, we set out to determine whether ALX is expressed in rat tissues and its potential role in modulating leukocyte trafficking with LXA(4) and ATL. 2. In rats, a stable analog of ATL, when given intravenously with two consecutive doses at approximately 60 microg kg(-1) each injection, significantly inhibited neutrophil infiltration (approximately 43%) and protein extravasation (approximately 42%) in a casein-induced peritonitis. 3. The rat orthologue of ALX was cloned from peripheral blood leukocytes encoding a putative G protein-coupled receptor (GPCR). It gave approximately 74 and approximately 84% homology, respectively to the deduced amino-acid sequences of the human and mouse ALX. 4. Tissue distribution analysis by RNase protection revealed that this rat receptor is expressed in tissues/cells, where LXA(4) displays physiological and pathophysiological roles, namely, lung, kidney and leukocytes. 5. The rat orthologue of ALX gave specific radioligand binding with [(3)H]LXA(4) and [(125)-Tyr]-annexin 1-derived peptide with apparent K(d) values of 5 and 820 nM, respectively, that are at levels comparable to those of the human ALX. 6. Activation of rat ALX inhibited tumor necrosis factor alpha-mediated nuclear factor kappaB activity in a ligand-dependent manner utilizing a luciferase reporter gene system. 7. Together, these results are the first demonstration of a rat ALX that is conserved in both structure and function suggesting that ALX plays key roles in regulating effector immune responses from murine to human species.
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PMID:A novel rat lipoxin A4 receptor that is conserved in structure and function. 1274 27


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