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)

Two major classes of mRNAs for the alpha-crystallin B chain (or alpha(B)crystallin), about 0.9 and 1.2 kilobases in length, are expressed in rat brain. To examine the structures of these mRNAs, we isolated cDNA clones from rat brain and genomic DNA from rat liver. Characterization of these clones as well as Northern blot analysis indicated that the various mRNAs differed in the lengths of their 5' leader sequences. RNase protection assays revealed that the gene for alpha-crystallin B chain contains multiple start sites. The transcriptional start sites of the longer mRNAs are preceded by a putative CAAT box and that of the shorter mRNA by a putative TATA box. The shorter mRNA encodes the alpha-crystallin B chain protein, whereas the longer mRNA contained three extra small open reading frames upstream of the AUG start codon for the protein. The shorter mRNA is abundant in lens, heart, muscle, and kidney, while the longer mRNAs are constitutively expressed at low levels in a wide variety of tissues. The shorter mRNA was increased by treatment with phorbol 12-myristate 13-acetate in rat C6 glioma cells. Since there is only a single copy of the alpha-crystallin B chain gene, our results indicate that the two classes of mRNAs are generated by alternative transcriptional initiation from different promoters and their expressions are regulated differentially.
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PMID:Multiple mRNAs of rat brain alpha-crystallin B chain result from alternative transcriptional initiation. 217 7

Second virial coefficients and hence covolumes for self-interaction of five proteins, viz. ribonuclease, ovalbumin, bovine serum albumin, catalase and alpha-crystallin, have been determined by analyzing the concentration dependence of the partition coefficient obtained from frontal chromatographic studies on either Fractogel TSK HW55 or porous glass beads. The resulting estimates of the effective radii essentially duplicate their Stokes counterparts and thereby provide further justification for assuming the approximate identity of the thermodynamic and hydrodynamic radii of hydrated globular proteins. Gel chromatographic evaluation of second virial coefficients for protein/dextran systems has led to elimination of the sphere/sphere model as a valid thermodynamic description of the space-filling effects in protein/polymer mixtures, since it does not predict the observed independence of covolume, expressed per unit mass of polymer, upon size of the polymer. This requirement is met by the sphere/rod model [Edmond, E. & Ogston, A. G. (1968) Biochem. J. 109, 569-576] and also by the sphere/flexible-segment model [Hermans, J. (1982) J. Chem. Phys. 77, 2193-2203]. Furthermore, similar studies of the effect of solute radius on covolume for interaction with dextran T70 attest to the adequacy of either model for predicting the thermodynamic nonideality arising from the inclusion of dextrans in protein solutions, and also provide the relevant calibration of the model.
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PMID:Thermodynamic nonideality in macromolecular solutions. Evaluation of parameters for the prediction of covolume effects. 237 80

Isoelectric focusing across a concentration gradient of urea was used to study the folding-unfolding and association-dissociation processes of proteins. Myoglobulin, albumin, RNase, papain, beta L- and alpha-crystallin were analyzed with this technique, and examples are given of visualized dissociation steps and of equilibrium-unfolding intermediates. Furthermore, a two-dimensional isoelectric focusing technique is presented that is useful to deduce whether a transition of a protein aggregate observed upon urea-gradient isoelectric focusing must be attributed to a change in the protein's tertiary or quaternary structure.
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PMID:Protein folding and aggregation studied by isoelectric focusing across a urea gradient and isoelectric focusing in two dimensions. 292 18

Oxidative mechanisms are thought to play a major role in several biological phenomena, including cataract formation. In the following studies we determined the relative levels of expression of the genes for the mRNAs for glutathione peroxidase (GPx), glutathione reductase (GR), CuZn-superoxide dismutase (CuZn-SOD) and catalase, in both the rat lens and liver. Northern blot hybridization methods were used to determine the mRNA size. The RNase protection method was used to determine levels of expression for these mRNAs plus levels of expression for alpha A-crystallin and gamma-crystallin mRNAs in the lens, and gamma-actin mRNAs in both the lens and the liver; using [32P]-labeled specific cRNA probes transcribed from the various cDNA clones for the mRNAs being studied. The data was normalized relative to the level of expression of alpha A-crystallin and gamma-actin mRNAs in the lens, and to gamma-actin mRNA in the liver. We find the levels of the mRNAs in the lens fall in the following descending order: GPx > GR > CuZn-SOD > catalase, in the same order as has been reported for the activities of the enzymes in the lens. In the liver, levels of these mRNAs were as follows: GPx > CuZn-SOD > GR > catalase. In the liver, CuZn-SOD mRNA was expressed at about four times the level found in the lens, GPx at three times, catalase at three times and GR at about the same level.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Levels of expression of the genes for glutathione reductase, glutathione peroxidase, catalase and CuZn-superoxide dismutase in rat lens and liver. 783 6

DeltaEF1 (delta-crystallin/E2-box factor 1) is a widely distributed repressor of transcription which binds at the E2-box sequence, CACCTG. It carries seven zinc fingers (Zf) in two clusters and a homeodomain in the middle as potential DNA-binding domains. We cloned the genomic gene encoding chicken deltaEF1 and analyzed its organization. The gene consisted of nine exons, the N-proximal Zf were encoded by exons 5 through 7, and the C-proximal Zf by exons 8 and 9. Exon 7 also coded for the large middle portion of the protein including the homeodomain. Promoter analysis and RNase-protection assay indicated that the gene is driven by a G+C-rich promoter without a TATA box, and the transcription start points (tsp) cluster around 20 bp from the start codon located in exon 1. cDNA and genomic sequences of the mouse delta EF1 were cloned and compared with the chicken sequence. The deduced amino acid (aa) sequence was highly conserved between the chicken and mouse deltaEF1, no only in DNA-binding motifs but also in other blocks (78% overall aa identity). More recently reported DNA-binding proteins, AREB6 (human) ZEB (human) and BZP (hamster), were attributed to homologues of deltaEF1, among which only AREB6 represented full-length sequence. It was also indicated that rodent deltaEF1 lacked exon 3.
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PMID:Organization of the gene encoding transcriptional repressor deltaEF1 and cross-species conservation of its domains. 896 4

This laboratory has introduced a chemical method for residue-specific protein cleavage and has provided a preliminary assessment of the suitability of microwave accelerated acid cleavage as a proteomic tool. This report is a continuing assessment of the fate of common protein modifications in microwave-accelerated acid cleavage. We have examined the cleavage of ribonuclease A and the related N-linked glycoprotein ribonuclease B, and the O-linked glycoprotein alpha crystallin A chain, using MALDI-TOF and LC-ESI-MS to identify the peptide products. RNase A and B each contain four disulfide bonds, and the addition of a reducing reagent, such as dithiothreitol, was found to be required to achieve efficient acidic proteolysis. The linkage of the glycosidic group to the asparagine side-chain in ribonuclease B was found not to be cleaved by brief microwave treatment in 12.5 % acetic acid. The distribution of the heterogeneous carbohydrate side chain in the glycopeptide products of acid cleavage was compared to that of the glycopeptide products of tryptic digestion. Hydrolysis within the carbohydrate chain itself is minimal under the conditions used. The O-linked side-chain on alpha crystalline A was found to be cleaved during acid cleavage of the protein.
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PMID:Extension of microwave-accelerated residue-specific acid cleavage to proteins with carbohydrate side chains and disulfide linkages. 1995 38