Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Rat ventricular cardiac muscle has previously been shown to contain exceptionally high levels of preproenkephalin mRNA (ppEnk mRNA). We have recently determined that the level of ppEnk mRNA is developmentally and hormonally regulated in rat ventricular cardiac muscle tissue and in cultured myocytes (J. P. Springhorn and W. C. Claycomb. Biochem. J. 258: 73-77, 1989). We demonstrate in the current study that heart ppEnk mRNA is structurally identical at the 5' end to brain ppEnk mRNA using a ribonuclease protection assay and that heart ppEnk mRNA can be translated in vitro using a rabbit reticulocyte lysate system. In vitro synthesized preproenkephalin peptides were immunoprecipitated with a polyclonal antibody directed to the carboxy-terminal seven amino acids of preproenkephalin. We have also established by radioimmunoassay that enkephalin-containing peptides are secreted from cultured neonatal and adult rat ventricular cardiac muscle cells. This secretion is linear with respect to time and can be stimulated by phorbol 12-myristate 13-acetate (PMA) and adenosine 3',5'-cyclic monophosphate (cAMP). It was determined by column chromatography that cAMP induced neonatal rat ventricular cardiac muscle cells to secrete Met5-enkephalin-Arg6-Phe7, whereas PMA plus 3-isobutyl-1-methylxanthine induced adult rat ventricular cardiac muscle cells to secrete Met5-enkephalin. These studies establish that ventricular heart muscle ppEnk mRNA can be translated and that enkephalin peptides are secreted from ventricular cardiac muscle cells.
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PMID:Translation of heart preproenkephalin mRNA and secretion of enkephalin peptides from cultured cardiac myocytes. 127 91

Sodium (Na) channel cDNAs were synthesized from RNA isolated from rat brain, cardiac muscle, and skeletal muscle. Partial cDNAs coding for the largest cytoplasmic loop of the Na channel were amplified with PCR. Sequence analysis of these cDNAs revealed that Na channel cDNAs originally described as brain genes were also expressed in both cardiac and skeletal muscle. Some of these cDNAs were isoforms that differed by insertions or deletions and can be explained by alternative choices of a 5' splice site. Southern blot analysis of genomic DNA confirmed the presence of introns in this region of the gene. Transcripts of multiple isoforms were detected with RNase protection in brain, heart, and skeletal muscle. Several conclusions can be drawn from the data. (1) Some rat sodium channel genes are transcribed in all excitable tissues studied here: brain, cardiac muscle, and skeletal muscle. (2) Each of these three tissues expresses multiple sodium channel genes. (3) Alternative splicing of sodium channel transcripts occurs in these tissues. (4) Expression of multiple genes and alternative splicing of the transcripts is responsible for at least seven different sodium channel mRNAs in skeletal muscle.
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PMID:Alternatively spliced sodium channel transcripts in brain and muscle. 131 93

To examine the relationship between the cardiac and skeletal muscle gene programs, the current study employs the regulatory (phosphorylatable) myosin light chain (MLC-2) as a model system. Northern blotting, primer extension, and RNase protection studies documented the high level expression of the cardiac MLC-2 mRNA in both mouse cardiac and slow skeletal muscle (soleus). Transgenic mouse lines harboring a 2100- or a 250-base pair rat cardiac MLC-2 promoter/luciferase fusion gene were generated, demonstrating high levels of luciferase activity in cardiac muscle, and only background luminescence in slow skeletal muscle and non-muscle tissues. As assessed by in situ hybridization, immunofluorescence, and luminescence assays of luciferase reporter activity in various regions of the heart, both the endogenous MLC-2 gene and the MLC-2 luciferase fusion gene were expressed exclusively in the ventricular compartment, with expression in the atrium at background levels. Point mutations within the conserved regulatory sites HF-1a and HF-1b significantly cripple ventricular muscle specificity, while mutation of the single E-box site was without effect, suggesting that ventricular muscle-specific expression occurs through an E-box-independent pathway. This study provides direct evidence that the cis regulatory sequences in the cardiac/slow twitch MLC-2 gene which confer cardiac and skeletal muscle-specific expression can be clearly segregated, suggesting that distinct regulatory programs may have evolved to control the tissue-specific expression of this single contractile protein gene in cardiac and skeletal muscle.
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PMID:Myosin light chain-2 luciferase transgenic mice reveal distinct regulatory programs for cardiac and skeletal muscle-specific expression of a single contractile protein gene. 137 40

We have cloned a cDNA (RMK2) coding for a Shaker type delayed rectifier K+ channel from a rat skeletal muscle cDNA library. The clone encodes a putative protein of 602 amino acids, identical with a rat brain K+ channel Kv1 (Swanson, R., Marshall, R., Smith, J. S., Williams, J. B., Boyle, M. B., Folander, K., Luneau, C. J., Antanavage, J., Oliva, C., Burhow, S. A., Bennet, C., Stein, R. B., and Kaczmarek, L. K. (1990) Neuron 4, 929-939). Northern blot analysis showed that RMK2 is expressed in skeletal and cardiac muscle. RNase protection analysis showed that the 3'-noncoding regions of the brain, cardiac, and skeletal muscle RMK2 transcripts are identical. Cloning of the gene confirmed that the protein is encoded by a single exon (Swanson et al. (1990) Neuron 4, 929-939). We expressed RMK2 in Xenopus oocytes and showed that it encodes noninactivating delayed rectifier K+ channels, resistant to block by external tetraethylammonium, with a small unitary conductance of 8.0 picosiemens. Coinjection of RMK2 and RCK1 (RMK1) (Baumann, A., Grupe, A., Ackermann, A., and Pongs, O. (1988) EMBO J. 7, 2457-2463; Koren, G., Liman, E. R., Logothetis, D. E., Nadal-Ginard, B., and Hess, P. (1990) Neuron 4, 39-51) into Xenopus oocytes resulted in the expression of currents that have tetraethylammonium inhibition curves that differ from the linear combination of inhibition curves of the two types expressed individually. Thus, RMK2 and RCK1 (RMK1) can form heteromultimers. RNA blot hybridization analysis revealed that the RMK2 transcript is developmentally regulated in a different manner in the rat skeletal muscle, ventricle, and atrium.
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PMID:Pretranslational mechanisms determine the type of potassium channels expressed in the rat skeletal and cardiac muscles. 171 80

A soluble ATP/Mg2-dependent proteolytic system from rabbit cardiac muscle has been identified (m ca. 310 kDa) and purified ca. 9-fold. This enzyme which splits the substrate [3H]globin and 125I-bovine serum albumin (125I-BSA) has many similarities to the ATP-dependent proteolytic enzyme system from reticulocytes which utilizes ubiquitin: 1) The specific activities in reticulocyte lysates and cardiac muscle extracts are of the same magnitude (0.5-1 arb. unit/mg). 2) The binding and elution behavior on DEAE-cellulose is similar. 3) In both cases the pH optimum (substrate 125I-BSA) is pH 7.6. 4) Both enzymes are inhibited by hemin, NEM and iodoacetate but not e.g. by leupeptin, or inhibitors of serine proteases. 5) Neither enzyme system can utilize ATP-analogs such as AMP-CPP, AMP-PCP, AMP-PNP or ATP-gamma-S. There are however also significant differences: 1) The enzyme system from cardiac muscle is fully active in the absence of ubiquitin and cannot be activated by this peptide. 2) The enzyme from cardiac muscle can degrade methylated BSA. 3) The cardiac muscle enzyme can be further purified on Sepharose 4B; the enzyme from reticulocytes is inactivated by this procedure. 4) The cardiac enzyme cannot be inactivated by ribonuclease as the reticulocyte counterpart. Although ubiquitin does not appear to play a role in the isolated ATP/Mg2-dependent proteolytic system from cardiac muscle, it is demonstrated for the first time that 125I-ubiquitin can be conjugated to a wide variety of cardiac muscle proteins in vitro in an ATP-dependent manner. Apparent molecular masses of major conjugates were: 185 kDa, 140 kDa, 85 kDa, 65 kDa, 46 kDa, 38 kDa and 36 kDa as estimated by discontinuous SDS gel electrophoresis. Addition of purified phosphorylase kinase to cardiac muscle extract changed the ubiquitination pattern by the appearance of two novel protein bands. It is concluded that the ATP/Mg2-dependent proteolytic system of cardiac muscle must be differentiated from the proteolytic system of reticulocytes mainly because of its ubiquitin-independence. Nevertheless the conjugation of 125I-ubiquitin to many muscle proteins is a strong indication for a crucial role of this interesting peptide in striated muscle.
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PMID:ATP-dependent proteolysis and the role of ubiquitin in rabbit cardiac muscle. 304 36

Duchenne muscular dystrophy (DMD), a sex-linked degenerative disorder of the muscle, is one of the most common lethal genetic diseases in man. It affects about one male in 3,500, with an estimated one-third of cases being caused by new mutations. A less severe disease, Becker's muscular dystrophy (BMD), maps to the same chromosomal locus and is most probably an allelic form of DMD. Both diseases are sometimes associated with various degrees of mental retardation; the molecular basis of these phenotypes is unknown (for review, see ref. 1). The giant DMD gene spans approximately 2,000 kilobases (kb) (0.05% of the human genome) and encodes a 14-kb mRNA. The tissue-specificity of its expression has not been precisely determined. Monaco et al., using Northern blots, reported expression of the gene in human fetal skeletal muscle and small intestine but not in human fetal brain, or in human cultured myoblasts and transformed B and T cells. More recently, expression was detected in mouse skeletal and cardiac muscle, but not in mouse brain. Here we show, using a ribonuclease protection assay, that the DMD gene is developmentally regulated in rat and mouse myogenic cell cultures, and that it is expressed in rat and mouse striated muscle, in mouse smooth muscle and in rat, mouse and rabbit brain. We could not detect transcripts in other non-muscle tissues.
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PMID:Expression of the putative Duchenne muscular dystrophy gene in differentiated myogenic cell cultures and in the brain. 334 Feb 14

The present study was undertaken to elucidate further the enzymatic changes in dystrophic muscle using multivariate analysis. The activities of 14 kinds of enzymes, including 6 exopeptidases, 4 endopeptidases, beta-N-acetyl-D-glucosaminidase, phosphatase, esterase, and ribonuclease, were examined in forelimb and hindlimb muscles as well as in cardiac muscle of dystrophic mice and their controls. Two principal components identified from the enzymatic spectrum proved to be related especially to aminopeptidases and to serine proteinases, respectively. The enzymatic changes in forelimb muscle were very similar to those in hindlimb muscle when both were compared to those in cardiac muscle. The changes in aminopeptidases were unique to the limb muscles, whereas those of serine proteinases were unique to cardiac muscle of dystrophic mice. In the future, more attention should be focused on the role of exopeptidases in pathogenetic mechanisms of muscular dystrophy, because of the possibility that they play a major role in the initial stage of muscular dystrophy.
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PMID:A multivariate study on enzymatic changes in limb muscles and heart muscle of dystrophic mice. 367 74

The activities of several lysosomal enzymes were assayed in control and in exercise-hypertrophied cardiac muscle of mice (Mus musculus). The repeated running program increased the activity of beta-glucuronidase (16.1%) in mouse cardiac muscle. Decreased activities of beta-N-acetylglucosaminidase (10.8%), acid ribonuclease (10.7%), and arylsulphatase (14.2%) were observed in the hypertrophied myocardium. The activities of acid deoxyribonuclease, cathepsin C, cathepsin D, and p-nitrophenylphosphatase as well as the activities of citrate synthase and cytochrome c oxidase, mitochondrial enzymes, were unaffected in cardiac muscle. We suggest that lysosomal enzyme responses are selective and highly different in physiologically and pathologically induced cardiac hypertrophies.
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PMID:Changes in lysosomal enzyme activities in exercise-induced cardiac hypertrophy of mice. 622 47

Acid hydrolase activities in skeletal and cardiac muscle were studied 5, 10 and 20 days after exhaustive intermittent running by untrained and endurance-trained mice. Exhaustion increased the activities of cathepsin D, beta-glucuronidase and ribonuclease, but not that of p-nitrophenylphosphatase in skeletal muscle of untrained mice. Activities were highest on the fifth day after exhaustion and decreased during the following two weeks. More intensive loading produced no changes in acid hydrolytic capacity in skeletal muscle of endurance-trained mice. Acid hydrolase activities in cardiac muscle of both untrained and trained mice were unaffected by exhaustive running. It is suggested that exhaustive running causes both lethal and sublethal hypoxic fiber injuries in the skeletal muscle of untrained mice but not in that of endurance-trained mice or in the cardiac muscle of animals of either group. These injuries manifest themselves as fiber necrosis (lethal) and as increased acid hydrolytic capacity in surviving fibers (sublethal).
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PMID:Acid hydrolase activities in mouse cardiac and skeletal muscle following exhaustive exercise. 719 24

cDNAs clones encoding the MLC1f and MLC3f proteins of Xenopus laevis have been isolated from a stage 42 cDNA library. Sequence analysis reveals that the amphibian MLC1f and MLC3f isoforms are similar to the mammalian and avian cognates. The two isoforms share a common 141-amino-acid carboxy-terminal regions. These are 49 and 9 residues long for the MLC1f and MLC3f isoforms, respectively. This suggests a genomic organization similar to the mammalian and avian genes, with two promoters and alternative splicing. The developmental expression of the MLC1f/3f mRNAs was studied by Northern blot and RNase protection and their spatial expression analyzed by in situ hybridization. Both the MLC1f and MLC3f mRNAs can be detected in the developing embryo from the end of gastrulation and accumulate rapidly in the somitic mesoderm. Expression of the MLC1f/3f gene can also be detected in animal cap explants which have been induced to form mesodermal derivatives by exposure to activin A or bFGF. However, unlike other muscle-specific markers, neither transcript from the MLC1f/3f gene can be detected in embryonic or adult cardiac muscle, their expression being restricted to somitic muscle. Together, these data demonstrate that expression of the MLC1f/3f gene provides a sensitive and specific marker for skeletal muscle differentiation. Ectopic expression of myogenic factors in animal caps induces the expression of the MLC1f/3f gene, suggesting that the amphibian gene, like its mammalian and avian counterparts, is a regulatory target for members of the MyoD family of transcription factors.
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PMID:The MLC1f/3f gene is an early marker of somitic muscle differentiation in Xenopus laevis embryo. 755 19


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