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:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genomic DNA clones containing the T-cell-specific human MAL gene were isolated. Restriction and sequence analysis revealed four exons and three introns. Each hydrophobic segment of MAL together with its adjacent hydrophilic sequence correlates closely with one exon of the gene. RNase protection analysis revealed that the previously described MAL mRNA, which contains the sequences present in the four exons, is the mRNA species predominant in T-cells. A remarkable similarity was found between the hydrophobicity pattern of MAL and those of the peripheral membrane protein 22 (PMP-22) and the 16-kDa proteolipid of vacuolar H(+)-ATPase. Direct evidence supporting that MAL is a proteolipid was obtained by extracting bacterial lysates expressing recombinant MAL protein with lipophilic solvents used to extract lipids. The use of two different antibodies raised against distinct peptides from the MAL molecule has allowed the localization of MAL in the endoplasmic reticulum of T-cells. This subcellular localization is in agreement with the presence of a RWKSS motif in the COOH-terminal tail of MAL, next to its last putative transmembrane domain, that fits with one of the consensus sequences (RXKXX) for residency in the endoplasmic reticulum for transmembrane proteins. A possible function for MAL protein in T-cells is discussed based on its subcellular localization and the unique lipid-like properties of the proteolipid proteins.
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PMID:Genomic structure and subcellular localization of MAL, a human T-cell-specific proteolipid protein. 813 41

By screening an Arabidopsis expression library with an antiserum against chloroplast envelope proteins, we have isolated a partial cDNA with an open reading frame that encodes a polypeptide similar to P-type cation-transporting ATPases. The corresponding genomic clone was isolated and the complete coding sequence was deduced after identification and mapping of introns. The gene has been designated PEA1 (plastid envelope ATPase) and the predicted polypeptide PEA1p. PEA1p has 946 amino acids and a molecular mass of 104 kDa. This protein is 40-44% identical to various mammalian plasma membrane Ca(2+)-ATPases but lacks the C-terminal calmodulin binding domain present in the mammalian polypeptides. When aligned with mammalian plasma membrane Ca(2+)-ATPases, PEA1p has a 70- to 80-amino acid N-terminal region that extends beyond the N terminus of these enzymes. This extension has some similarity to the transit peptide of the plastid envelope phosphate translocator and may function to target the protein to the plastid. Antibodies raised against a portion of PEA1p recognize a single 90- to 95-kDa polypeptide in chloroplast inner envelope preparations. Transcript abundance as determined by RNase protection was found to be 7- to 9-fold higher in roots than in leaves. Possible roles for a plastid envelope calcium pump are suggested.
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PMID:Characterization of a gene encoding a Ca(2+)-ATPase-like protein in the plastid envelope. 823 57

Recently, a putative distal colon H(+)-K(+)-ATPase alpha-subunit has been identified and characterized (M. S. Crowson and G. E. Shull. J. Biol. Chem. 267:13740-13748, 1992). In the present study, we report the tissue and cell expression of this putative H(+)-K(+)-ATPase. The results indicate that, first, in the gut, the putative H(+)-K(+)-ATPase alpha-subunit is restricted to the distal part of the colon and is predominantly expressed in surface epithelial cells, in marked contrast to the alpha 1-subunit of Na(+)-K(+)-ATPase that is also expressed in glands. These data suggest that the H(+)-K(+)-ATPase alpha-subunit is a potential marker for terminal differentiation of distal colon. Second, in the uterus, the putative H(+)-K(+)-ATPase is restricted to the region of the myometrium between the inner and midmuscular zone that is very rich in vascular supply and nerve cells. This striking expression suggests that the H(+)-K(+)-ATPase may not be involved in the control of pH and potassium concentration of the uterine fluid but rather in distinct functions of vascular and/or nerve cells. Third, with the use of three independent and different approaches (Northern blot analysis, ribonuclease protection assay, and in situ hybridization), we were unable to detect any significant amount of H(+)-K(+)-ATPase transcripts in kidney tissue. Our data suggest that the putative distal colon H(+)-K(+)-ATPase is probably distinct from the kidney isoform. Finally, we report the sequence of a set of degenerate oligonucleotides that are useful to clone alpha-subunits of the Na(+)-K(+)-/H(+)-K(+)-ATPase gene family in different tissues and different species.
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PMID:A putative H(+)-K(+)-ATPase is selectively expressed in surface epithelial cells of rat distal colon. 823 99

Fluorescence techniques have been used to investigate the interaction of bovine 70-kDa heat shock cognate protein (Hsc 70) with small molecular weight peptides and myo-inositol monophosphatase. The emission properties of Hsc 70 remain invariant upon addition of ATP. The results of steady-state fluorescence indicate that the tryptophan residues of Hsc 70 are exposed to the rapidly relaxing aqueous solvent. Binding of residues 1-20 of ribonuclease A (RNase S-peptide) to Hsc 70 causes protein fluorescence quenching which was used to determine a dissociation constant Kd = 2.7 microM for the binary Hsc 70.RNase S-peptide complex. The octapeptide corresponding to the NH2-terminal portion of sickle cell hemoglobin recognizes Hsc 70 and binds with a Kd = 9.3 microM. Binding of RNase S-peptide to Hsc 70 produces a small enhancement of ATPase activity. Unfolded myo-inositol monophosphatase, tagged with the fluorescent probe 5-[2-(2-iodoacetamido)ethylamino]-1-naphthalenesulfonic acid, recognizes Hsc 70; the formation of a stable complex was detected by steady-state emission anisotropy measurements. The rate and extent of recovery of catalytic activity of unfolded myo-inositol monophosphatase is not influenced by Hsc 70. It is suggested that interaction of Hsc 70 with unfolded proteins in the cell may be able to delay the formation of misfolded structures.
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PMID:Interaction of 70-kDA heat shock cognate protein with peptides and myo-inositol monophosphatase. 827 5

G63, the major surface glycoprotein of Leishmania chagasi promastigotes, increases 11-fold in amount as promastigotes grow from logarithmic to stationary phase. Transcripts from three different classes of gp63 genes are differentially expressed during this development (Ramamoorthy, R., Donelson, J. E., Paetz, K. E., Maybodi, M., Roberts, S. P., and Wilson, M. E. (1992) J. Biol. Chem. 267, 1888-1895). We studied the effect of protein synthesis inhibitors on gp63 mRNAs. The steady state level of log class gp63 RNA, expressed primarily in logarithmic phase promastigotes, increased 16.5-fold after incubation in cycloheximide. A similar increase in log gp63 RNAs was caused by inhibitors that block different steps in translation. In contrast, the levels of stationary class gp63 RNA, expressed in stationary phase parasites, and constitutive class gp63 RNA, expressed throughout promastigote growth, increased only 2.3- and 1.5-fold, respectively. The latter was not statistically significant. Nuclear run-on assays showed that the cycloheximide effect was not due to an increased rate of transcription. However, the t1/2 of log RNAs was prolonged 6.5-fold after incubation in cycloheximide, in contrast to a 1.7-fold increase in the t1/2 of ATPase RNA, suggesting that cycloheximide specifically stabilizes log gp63 mRNAs. Thus, a highly labile negative regulatory protein, such as an RNase, may specifically target log gp63 RNAs for degradation.
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PMID:The effect of ongoing protein synthesis on the steady state levels of Gp63 RNAs in Leishmania chagasi. 834 Mar 97

Previous work demonstrated that the rabbit smooth muscle myosin heavy chain gene showed sequence divergence at the 25kDa/50kDa junction of the S1 subfragment when compared to chicken gizzard and chicken epithelial nonmuscle myosin. RNase protection analysis with a probe spanning this region detected two partially protected fragments which were not present in RNA from vascular tissue and only found in RNA from visceral tissue. The polymerase chain reaction was used to amplify a 162bp product from primers spanning the putative region of divergence and DNA sequence analysis revealed a seven amino acid insertion not previously detected in other characterised cDNA clones. RNase protection analysis using the PCR product as probe showed that the inserted sequence was expressed exclusively in RNA from visceral tissue. Similar RNA analysis showed that the visceral isoform was not expressed in 20 day fetal rabbit smooth muscle tissues. These results indicated that the new visceral isoform was expressed in a tissue-specific and developmentally regulated manner. Genomic DNA sequencing and mapping of the exon-intron boundaries showed that the visceral isoform was the product of cassette-type alternative splicing. The inclusion of a visceral-specific sequence near the Mg-ATPase domain and at the 25kDa/50kDa junction suggests that the visceral isoform may be important for myosin function in smooth muscle cells.
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PMID:Tissue-specific and developmentally regulated alternative splicing of a visceral isoform of smooth muscle myosin heavy chain. 846 39

Somatostatin (SMS) is administered to patients with short bowel syndrome and enterocutaneous fistulae. Previous studies have shown detrimental effects of SMS on intestinal adaptation after bowel resection. We examined whether administration of epidermal growth factor (EGF) could reverse the deleterious effects of SMS seen after enterectomy. Sixty-four Sprague-Dawley rats underwent an 80% small bowel resection or transection as control. Rats received either SMS at 50 ng x kg(-1) x h(-1), EGF/Urogastrone at 1.5 microg x kg(1-) x h(-1), or both via subcutaneous miniosmotic pumps. Samples were obtained at 1 day and 1 week after surgery for histologic examination, analysis of apical Na+/glucose cotransporter protein and mRNA expression, and analysis of basolateral Na+/K+ ATPase protein and mRNA expression. Protein expression was analyzed by Western blotting whereas mRNA expression was compared by ribonuclease protection assay. Histologically, villus to crypt length after intestinal resection showed increased adaptation in EGF/SMS vs SMS treated animals in both jejunum and ileum. Analysis of mRNA and protein of epithelial transporters show early increases when EGF is administered with SMS vs SMS only. We conclude that combination therapy using EGF and SMS may be beneficial to intestinal adaptation after small bowel resection. Both histologic and molecular data suggest an enhanced absorptive potential and adaptation of the remaining intestine when EGF is administered.
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PMID:Epidermal growth factor improves intestinal adaptation during somatostatin administration in vivo. 866 Nov 91

Recent pharmacological and functional studies have suggested the presence of more than one alpha-1 adrenergic receptor subtype in human corpus cavernosum (HCC). In this study, we sought to identify the alpha-1 adrenergic receptor (alpha 1-AR) subtypes expressed in HCC whole tissue and in trabecular smooth muscle subcultured from this tissue. We have utilized RNase protection assays and in situ hybridization (ISH) techniques to identify and localize these receptor subtypes. RNase protection assays of mRNA isolated from whole tissue demonstrated the presence of mRNA transcripts for three alpha 1-AR receptor subtypes (alpha 1d, alpha 1b, and alpha 1a). alpha 1d-AR and alpha 1a-AR appear to be more abundant than alpha 1b-AR. The identification and localization of mRNA for alpha 1-AR subtypes in whole tissue was demonstrated by RNA protection assays and ISH analysis. Immunocytochemical analysis of alpha 1-AR by an antipeptide antibody developed against a specific amino acid sequence derived from alpha 1d-AR subtype demonstrated specific staining of the smooth muscle cells, suggesting the expression of alpha 1d-AR subtype. In cultured HCC smooth muscle cells (HCC SMC), phenylephrine,alpha 1-AR agonist stimulated Na+/K+ ATPase activity, suggesting the presence of functional alpha 1-AR. RNase protection assay of mRNA isolated from HCC SMC grown in culture further demonstrated the presence of mRNA transcripts for alpha 1d-AR and alpha 1a-AR subtypes. ISH analysis and confocal microscopy also indicate that the SMC express the alpha 1d-AR and alpha 1a-AR subtypes. The data presented suggests that HCC and SMC derived from this tissue express at least three alpha 1-AR subtypes. Identification of these receptor subtypes should allow characterization of the functional role of these receptor subtypes in regulation of trabecular smooth muscle tone and penile detumescence.
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PMID:Identification of alpha 1-adrenergic receptor subtypes in human corpus cavernosum tissue and in cultured trabecular smooth muscle cells. 872 94

Channel inducing factor (CHIF) is a novel cDNA recently cloned from a rat distal colon cDNA library of dexamethasone-treated animals. While its expression in Xenopus oocytes evokes a potassium channel activity similar to that induced by Isk (minK), its cellular role is not clear. CHIF exhibits significant homologies with proteins that are putatively regulatory (phospholemman, gamma-subunit of Na(+)-K(+)-ATPase, Mat-8) while it differs from the small-conductance potassium channel Isk. We have studied the tissue specificity of CHIF expression in rat by in situ hybridization. CHIF is selectively present in the distal parts of the nephron (medullary and papillary collecting ducts and end portions of cortical collecting tubule) and in the epithelial cells of the distal colon. No expression of CHIF was found in renal proximal tubule, loop of Henle and distal tubule, proximal colon, small intestine, lung, choroid plexus, salivary glands, or brain. To gain some insight into CHIF function, we have investigated, using in situ hybridization and ribonuclease protection assay, whether CHIF mRNA expression could be altered in some situations. In the distal colon, corticosteroid hormones, sodium restriction, low-potassium diet, and metabolic acidosis significantly increased CHIF mRNA expression. In the kidney, metabolic acidosis was the only condition that showed an increase in CHIF mRNA expression. Some of these treatments also altered the expression of the colonic H(+)-K(+)-ATPase mRNA. In summary, CHIF mRNA is selectively expressed in the medullary collecting duct of the kidney and in the epithelium of the distal colon; its expression varies differently in these two target tissues after alterations in corticosteroid status, potassium depletion, and metabolic acidosis. The precise cell-specific functions of CHIF remain to be established.
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PMID:Cellular localization and regulation of CHIF in kidney and colon. 884 4

SPAI, originally isolated as a sodium/potassium-ATPase inhibitor and now considered to be a proteinase inhibitor of unknown specificity based on its similarity to elafin (an elastase inhibitor), is a new type of plasma protein that has a transglutaminase substrate domain, which serves as an anchoring sequence to be covalently cross-linked at target sites. To determine the source of SPAI, we carried out in situ hybridization and immunohistochemistry using an antisense cRNA probe and an antiserum against recombinant SPAI, respectively. Since previous RNase protection analysis had indicated that SPAI mRNA is almost exclusively expressed in the porcine small intestine, we used its frozen sections for the staining. The lower crypt was decorated with both the cRNA probe and antiserum, indicating that SPAI is synthesized and secreted by the enteroendocrine cells located near the crypt base. The native form of SPAI was also characterized by Western blotting. This result together with the previous biochemical and molecular biological characterizations may set the stage for identifying the physiological roles of the conceptually very interesting protein SPAI.
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PMID:Cryptic origin of SPAI, a plasma protein with a transglutaminase substrate domain and the WAP motif, revealed by in situ hybridization and immunohistochemistry. 893 75


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