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)

Sequence analysis of 5'-[32P] labeled tRNA and eukaryotic mRNA using an adaptation of a method recently described by Donis-Keller, Maxam and Gilbert for mapping guanines, adenines and pyrimidines from the 5'-end of an RNA is described. In addition, a technique utilizing two-dimensional polyacrylamide gel electrophoresis for identification of pyrimidines within a sequence is described. 5'-[32P] Labeled rabbit beta-globin mRNA and N. crassa mitochondrial initiator tRNA were partially digested with T1- RNase for cleavage at G residues, with U2-RNase for cleavage at A residues, with an extracellular RNase from B. cereus for cleavage at pyrimidine residues and with T2-RNase or with alkali for cleavage at all four residues. The 5'-[32P] labeled partial digestion products were separated according to their size, by electrophoresis in adjacent lanes of a polyacrylamide slab gel and the location of G's, A's and of pyrimidines extending 60-80 nucleotides from the 5'-end of the RNA determined. Two-dimensional polyacrylamide gel electrophoresis was used to separate the 5'-[32P] labeled fragments present in partial alkali digests of a 5'-[32P] labeled mRNA. The mobility shifts corresponding to the difference of a C residue were distinct from those corresponding to a U residue and this formed the basis of a method for distinguishing between the pyrimidines.
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PMID:Sequence analysis of 5'[32P] labeled mRNA and tRNA using polyacrylamide gel electrophoresis. 2 17

Rabbit globin complementary DNA made with RNA-dependent DNA polymerase (reverse transcriptase) was used as a template for in vitro synthesis of 32P-labeled RNA and deoxysubstituted RNA. The sequences of the nucleotides in most of the fragments resulting from combined ribonuclease T1 and alkaline phosphatase digestion have been determined. In addition, the 3' nearest neighbor was determined for several fragments resulting from digestion with T1 ribonuclease. The utility of the deoxysubstitution technique was demonstrated by the ease with which the sequences of pyrimidine-rich fragments could be determined. Many sequences thus determined were long enough to fit uniquely with the alpha- or beta-globin amino acid sequences. The positions of these fits were found to be clustered, leading us to believe that only certain regions of the complementary DNA are transcribed by Escherichia coli RNA polymerase. Other unique characteristics of RNA synthesis from a complementary DNA template include a high yield of free poly(A) and the fact that one must use low rather than high salt buffers to obtain transcripts of high molecular weight.
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PMID:Rabbit globin mRNA: analysis of T1 RNAse digestion fragments. 6 35

In a patient with homozygous betaO-thalassemia in whom studies of reticulocyte hemoglobin synthesis showed no beta-globin chain synthesis in vivo and in vitro, molecular hybridization studies revealed RNA sequences complementary to beta-globin cDNA. The fact that these sequences were authentic beta-globin mRNA was shown by fingerprint analysis of T1 ribonuclease-digested mRNA and by sequencing of oligonucleotides unique to beta-globin mRNA. The beta-mRNA that failed to direct beta-globin chain synthesis was not detectably shortened or degraded and contained poly(A) sequences.
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PMID:Authentic beta-globin mRNA sequences in homozygous betaO-thalassemia. 26 54

The 5'-terminal structures of murine alpha- and beta-globin mRNA were determined after incubating cells of the erythropoietic spleens of mice with [methyl-3H]methionine. Globin mRNA was obtained from total cellular RNA by oligo(dT)-cellulose chromatography followed by elution of mRNA from formamide gels after electrophoresis. The globin mRNA was then hydrolyzed with KOH or digested with a combination of RNase T2 and bacterial alkaline phosphatase, and 5'-terminal structures were isolated by DEAE-cellulose chromatography. The methylated nucleotides of these 5'-structures were determined following digestion with specific ribonucleases and bacterial alkaline phosphatase. Analyses of mRNA fractions enriched for either alpha- or beta-mRNA gave similar results. Our data indicate that murine alpha- and beta-globin mRNAs are identical through the first three nucleotides and that partial dimethylation exists at the second position: m7G(5')ppp(5') [m6Am/Am]pCmpNp.
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PMID:The 5'-terminal structures of murine alpha- and beta-globin messenger RNA. 83 40

Transient transfection is a widely used tool for the identification of cis-acting regulatory elements. These elements are detected by their effect on the expression of a reporter gene, which is quantified by measuring the reporter gene product in the form of mRNA, protein (hGH), or enzymes (CAT, luciferase). Measurements of mRNA levels have several advantages over enzyme or protein assays. However, mRNA quantification by RNase protection or S1 mapping has considerably lower signal-to-background ratio than protein assays and is therefore less sensitive. In this paper we report the development of a system that takes advantage of the polymerase chain reaction (PCR) to quantify rabbit beta-globin reporter gene expression. Cells are co-transfected with constructs whose activity is to be tested and a reference plasmid with a small deletion in the second exon of the beta-globin gene. We show that the ratio of the two amplified cDNA signals is a highly reliable measure of test gene expression. The sensitivity of this assay is at least 1000-fold higher than RNase protection.
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PMID:A PCR-based assay for reporter gene expression. 147 39

Erythropoiesis in vertebrates is characterized by sequential changes in erythropoietic site, erythroblast morphology, and hemoglobin synthesis. We have examined the expression of globin chains and the major erythroid transcription factor GATA-1 (previously known as GF-1/NF-E1/Eryf 1) from days 7.5 to 17.5 of mouse development. mRNAs for embryonic (epsilon y2, beta H1, and zeta) and adult (alpha and beta) globin chains were quantitated by RNase protection assays. Switching of globins within the alpha-globin cluster (alpha and zeta) was not strictly coordinated with that within the beta-globin cluster (epsilon y2, beta H1, and beta). Regulation of globin switches during development was primarily transcriptional. Of particular note, we found two developmental switches (beta H1 to epsilon y2 and epsilon y2 to beta) in the mouse, more analogous than previously thought to shifts found in human development. The erythroid transcription factor GATA-1, believed to be a principal regulator of genes expressed in erythroid cells, first appeared in the embryo in yolk sac at the time of blood island formation and remained at a low level during embryonic erythropoiesis (8 to 11 days) relative to that found later in fetal liver (12 to 15 days). The rise in GATA-1 mRNA in fetal liver paralleled and preceded the rapid accumulation of adult beta-globin RNA. RNase protection assays and a GATA-1-specific peptide antiserum were used to establish that a single GATA-1 polypeptide is expressed throughout mouse development. Overall, these findings suggest that the levels of this erythroid transcription factor during development may contribute to the differential gene activation characteristic of definitive versus primitive erythropoiesis.
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PMID:Regulated expression of globin chains and the erythroid transcription factor GATA-1 during erythropoiesis in the developing mouse. 170 Oct 19

We have used alpha-oligomers as antisense oligonucleotides complementary to three different sequences of the rabbit beta-globin mRNA: a region adjacent to the cap site, a region spanning the AUG initiation codon or a sequence in the coding region. These alpha-oligonucleotides were synthesized either with a free 5' OH group or linked to an acridine derivative. The effect of these oligonucleotides on mRNA translation was investigated in cell-free extracts and in Xenopus oocytes. In rabbit reticulocyte lysate and in wheat germ extracts oligomers targeted to the cap site and the initiation codon reduced beta-globin synthesis in a dose-dependent manner, whereas the target mRNA remained intact. The anti-cap alpha-oligomer was even more efficient that its beta-counterpart in rabbit reticulocyte lysate. In contrast, only the alpha-oligomer, linked to the acridine derivative, complementary to the cap region displayed significant antisense properties in Xenopus oocytes. Therefore initiation of translation can be arrested by oligonucleotide/RNA hybrids which are not substrates for RNase-H.
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PMID:Inhibition of translation initiation by antisense oligonucleotides via an RNase-H independent mechanism. 185 May 11

A method to enrich large size DNA fragments obtained by digestion with rare cutting restriction endonucleases was developed and applied for the isolation of a 150 kb SfiI fragment containing the beta-globin gene cluster. The digested DNA is rendered single stranded at the ends by diffusing a strand specific exonuclease into an agarose plug containing DNA. The plug is melted and solution hybridization is then performed with a bridge RNA containing specific sequences from the end of a desired fragment linked to a common probe sequence. The common probe sequence is annealed to a biotinylated RNA and the resulting tripartite hybrid is retained onto a solid matrix containing avidin and specifically released by ribonuclease action. Enrichments of greater than 350 fold have been achieved consistently. Such directed purification of large DNA fragments without cloning can considerably expedite mapping and gene localization in a complex genome and facilitate the construction of sublibraries from defined regions of the genome.
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PMID:Selective enrichment of a large size genomic DNA fragment by affinity capture: an approach for genome mapping. 233 56

The applicability of ribonuclease cleavage at mismatches in RNA:DNA duplexes (RNase cleavage method) for determining nucleotide variant rates has been examined in a Japanese population. DNA segments of various lengths obtained from 4 different regions of a normal and 3 thalassemic cloned human beta-globin genes were inserted into transcription vectors. Sense and antisense RNA probes uniformly labeled with 32P were prepared. When RNA probes of 771 nucleotides (nt) or less were hybridized with cloned DNAs and the resulting duplexes were treated with a mixture of RNases A and T1, the length of products agreed with theoretical values. Twelve possible mismatches were examined. Since both sense and antisense probes were used, uncleavable mismatches such as G:T and G:G which were made from one combination of RNA and DNA strands could be converted to the cleavable C:A and C:C mismatches, respectively, by using the opposite combination. Deletions and insertions of 1 (G), 4 (TTCT), 5 (ATTTT) and 10 (ATTTTATTTT) nt were easily detected. A polymorphic substitution of T to C at position 666 of the second intervening sequence (IVS2-666) of the beta-globin gene was detected using genomic DNAs from cell lines established from the peripheral B lymphocytes of 59 unrelated Japanese from Hiroshima or those amplified by polymerase chain reaction (PCR). The frequency of the gene with C at the IVS2-666 (allele C) was 0.48 and that of the gene with T (allele T) was 0.52. The associations of the 2 alleles were in agreement with Hardy-Weinberg proportions. No contradiction to Mendelian inheritance was observed in the results obtained from 11 family studies. Two new polymorphic substitutions of C to A and A to T were detected at nucleotide positions 1789 and 1945 from the capping site, respectively, using genomic DNAs amplified by PCR. The feasibility of the RNase cleavage method combined with PCR for large-scale screening of variation in chromosomal DNA is discussed.
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PMID:Detection of deletions, insertions and single nucleotide substitutions in cloned beta-globin genes and new polymorphic nucleotide substitutions in beta-globin genes in a Japanese population using ribonuclease cleavage at mismatches in RNA:DNA duplexes. 238 39

We have developed a new procedure for the rapid preparation of undegraded total RNA from cultured cells for specific quantitation by dot blotting analysis. Pelleted cells are resuspended in hypotonic solution containing a ribonuclease inhibitor and heparin and disrupted by freeze-thaw. Heparin is employed as an agent for nuclear lysis, dissociation of chromosomal protein, and release of mRNA from rough endoplasmic reticulum. We eliminate chromosomal DNA by digestion with DNase I and denature the RNA in the lysate with formaldehyde. After centrifugation to remove debris, the supernatant is used directly for dot blotting. All manipulations are performed in the same microfuge tube and recovery of RNA is quantitative. The procedure is especially useful for processing large numbers of samples. We illustrate its versatility by analysis of specific RNAs in Drosophila, rat, and human cell lines. In reconstruction experiments, less than 80 molecules per cell of a small RNA (beta-globin) can be detected under highly stringent hybridization conditions, using only moderately labeled double-stranded plasmid DNA probes and short film exposures.
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PMID:Isolation of RNA for dot hybridization by heparin-DNase I treatment of whole cell lysate. 244 24


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