Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genes for urea cycle enzymes including liver-type arginase are expressed mainly in the liver and are regulated developmentally, nutritionally, and hormonally in a coordinated manner. The promoter region of the rat arginase gene was investigated with an in vitro transcription system using nuclear extracts prepared from rat tissues. Accurate initiation of the transcription in liver nuclear extracts was confirmed by runoff analysis and S1 nuclease mapping. The arginase promoter was transcribed more efficiently in liver nuclear extracts than in brain extracts, reproducing the in vivo tissue specificity qualitatively. Analysis of deletion mutants of the 5'-flanking region in liver nuclear extracts revealed a positive regulatory region spanning nucleotides -90 to -51 relative to the transcription start site. Overlapping this region, two protected areas were detected by DNase I footprinting. Competition analysis with synthetic oligonucleotides showed that the more downstream protected area was occupied, in a mutually exclusive manner, by two factors each related to CTF/NF-1 and Sp1. The other more upstream protected area was recognized by a factor related to the liver-enriched transcription factor C/EBP, which was recently shown to interact with regulatory regions of two other urea cycle enzyme genes.
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PMID:In vitro analysis of the rat liver-type arginase promoter. 202 18

A solution hybridization/RNase protection assay with riboprobes was developed to quantitate apolipoprotein mRNA concentrations. Previously, radiolabeled DNA probes have been used in solution hybridization/S1 nuclease protection assays for this purpose. The new assay requires less time for probe preparation and hybridization compared to previous assays. In addition, the vector used for riboprobe preparation can also be used to conveniently produce cRNA required to generate the standard curve to quantitate absolute apolipoprotein mRNA levels. The solution hybridization RNase protection assay was used to quantitate apoB, A-I, and E mRNA levels in four human hepatoma cell lines, HepG2, Hep3B, WRL-68, SK-Hep2. HepG2 and Hep3B, but not WRL-68 and SK-Hep2 cells had concentrations of all three apolipoprotein mRNAs comparable to liver in vivo. These data suggest that HepG2 and Hep3B are suitable models to study liver specific apolipoprotein gene expression.
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PMID:A solution hybridization/RNase protection assay with riboprobes to determine absolute levels of apoB, A-I, and E mRNA in human hepatoma cell lines. 216 16

Highly purified DNA obtained from calf thymus nuclei was found to cleave after reaction with a chelating agent and subsequent dialysis against 0.01 M phosphate. During the cleavage release of proteineous material into the dialysate was observed. By means of anion exchange resin column chromatography, this material was separated into 9 main fractions. Two of these fractions P1 and P5) were found to contain the amino acids phosphoserine, asp, thr, ser, glu, gly, ala, val, ile, leu, and arg, as well as metal ion complexes of phosphoserine. The complexes were dissociated by Chelex 100 treatment. The proportion of phosphoserine was much greater in P5 than in P1. P1 and P5 contained essentially no nucleotide material. All other fractions (P2, P3, P3a, P4, P5a, P6, P7, P8, P6a, P9) were found to contain ribonucleotides and deoxynucleotides. The deoxynucleotide content was about 10% of total nucleotide content. After a deionizing treatment with Chelex, the amounts of nucleotides were extensively reduced to a level corresponding to about 1 nucleotide of 10 amino acids. In separate experiments, commercial DNA (S-DNA) was ultrasonicated, and digested with pancreatic DNAase, exonuclease III, and S1 nuclease. From DEAE Sephacel chromatography of this material the fraction obtained having the highest proportion of protein aceous material was hydrolyzed with Pronase and again chromatographed on DEAE Sephacel. From this fractionation a single fraction containing deoxynucleotides and amino acids was found. The mixture obtained by hydrolysis of this fraction with snake venom diesterase and was again rechromatographed, which revealed two peaks, one corresponding to deoxynucleotide material and a second one to a mixture of 4 amino acids, phosphoserine, asp, glu, and gly. From this it was concluded that the fraction used for diesterase digestion consisted of deoxynucleotide-amino acids, with covalent diester bonds between their deoxynucleotide and amino acid portions. The results indicate that in purified S-DNA phosphopeptides are linked through covalent bonds to the terminal deoxynucleotide residues.
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PMID:Phosphopeptides in highly purified calf thymus DNA. 282 22

Liver-type arginase (EC 3.5.3.1) catalyzes the last step of urea synthesis and is expressed specifically in the liver of ureotelic animals. Expression of liver arginase is developmentally and hormonally regulated in coordination with other urea cycle enzymes. The gene for the rat enzyme was cloned and the structure determined. This gene is 12 kilobases long and is split into eight exons. All of the splice donor and acceptor sites conform to the GT/AG rule. The transcription initiation site was determined by nuclease S1 mapping and primer extension. A "TATA box"-like sequence and a "CAAT box"-like sequence are present 27 and 60 bases upstream from the cap site, respectively. Upstream and downstream from the cap site, there are several sets of direct repeats and inverted repeats and several sequences resembling the transcription factor Sp1 binding sites, the enhancer core sequences, the glucocorticoid receptor binding sites, the 12-O-tetradecanoylphorbol-13-acetate responsive elements, and the putative elements for liver-specific expression of albumin genes. A 15-nucleotide sequence in the 5'-flanking region of the arginase gene is highly homologous with sequences in the 5'-flanking regions of the genes for rat ornithine carbamoyltransferase (EC 2.1.3.3) and for human argininosuccinate synthetase (EC 6.3.4.5), other two enzymes of the urea cycle.
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PMID:Structural organization of the gene for rat liver-type arginase. 289 37

The gene for human liver-type arginase (EC 3.5.3.1), a urea cycle enzyme, was cloned and the structure was determined. This gene is 11.5 kilobases long and is split into 8 exons. The cap site was determined by nuclease S1 mapping and primer extension. A "TATA box"-like sequence is located 28 bases upstream from the cap site, and a sequence similar to the binding sites of the transcription factor CTF/NF1, a "CAAT box"-binding protein, is located 72 bases upstream. In the 5' end region, sequences resembling the glucocorticoid responsive elements, the cAMP responsive elements, and the enhancer core sequences are present. The immediately 5' flanking region of the human gene up to position -105 is 84% identical with the corresponding segment of the rat gene. In this region of the human gene, one DNase I-protected area and several hypersensitive cleavage sites were detected by footprint analysis, using nuclear extracts from the rat liver. The protected area contains the sequence similar to the binding sites of CTF/NF1 and also overlaps with the sequence resembling the glucocorticoid responsive elements.
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PMID:Human liver-type arginase gene: structure of the gene and analysis of the promoter region. 317 33

Highly purified DNA from calf thymus nuclei (N-DNA) was found to cleave after reaction with a chelating agent and subsequent dialysis. During the cleavage phosphopeptides (PPs) were released into the dialysates. At the end of the cleavage, approximately one half of the PP material remained with the DNA. Since it was so strongly bound, it was considered to be retained in the DNA structure by covalent bonding. In order to confirm this, a commercial DNA (S-DNA) was ultrasonicated and digested with pancreatic DNAase, exonuclease III, and S1 nuclease. DEAE Sephacel chromatography of the digested material yielded 5 fractions. The fraction 2, having the highest proportion of proteinaceous material, was digested with Pronase. Amino acid analysis of the hydrolysis mixture yielded phosphoserine (Pser), asp, thr, ser, glu, gly, ala, val, ile, leu, and arg. The mixture was chromatographed again on DEAE Sephacel. From this a single fraction, number 5, was found to contain both deoxynucleotides and the amino acids, Pser, asp, ser, glu, and gly in a molar ratio of greater than 7:3:2:2:5. The mixture obtained by hydrolysis of this fraction with snake venom diesterase was again chromatographed on DEAE Sephacel. This fractionation gave two main peaks, one corresponding to the same 5 amino acids and the other to deoxynucleotide material. From this it was concluded that the fraction used for diesterase digestion consisted of deoxynucleotide-amino acids, with covalent diester bonds between the deoxynucleotide and amino acid portions.
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PMID:Evidence for covalent binding between phosphopeptides and terminal deoxynucleotides in highly purified calf thymus DNA. 347 28

Since apolipoprotein A-I (apo A-I) and HDL stimulate the expression of the placental hormone human placental lactogen (hPL), experiments were performed to determine whether the human placenta synthesizes apo A-I. Western blot analysis of a partially purified extract of human term placenta with an antiserum to human apo A-I yielded an immunoreactive band with an apparent mass of approximately 23.5 kDa, which is smaller than human plasma apo A-I (28 kDa). HPLC chromatography of the partially purified placental extract on a preparative reverse-phase C-18 column yielded two fractions that reacted to the apo A-I antiserum. The mass of both fractions by mass spectral analysis was 22 721 daltons, and N-terminal amino acid sequences were identical to the first four amino acids of apo A-I (Asp, Glu, Pro, Pro). The apo A-I-like protein was not a proteolytic product of apo A-I since Northern analysis of placental RNA with a 641 bp apo A-I cDNA fragment encoding most of the 5' region of the apo A-I mRNA detected a single band of 850 nt, which is smaller than the size of apo A-I mRNA (1100 nt). Placental mRNA, however, did not hybridize with a 3' apo A-I riboprobe, indicating that the 3' region of the apo A-I-like mRNA is different from that of apo A-I mRNA. Differences in the mRNAs were confirmed by S1 nuclease analysis of placental RNA with a cDNA probe that included the 3' end of the apo A-I cDNA and by RT-PCR analysis with a series of oligonucleotide primers that span the entire cDNA for apo A-I. Since there is only a single apo A-I gene in the human genome, these findings strongly suggest that human placental tissue expresses a novel 22.7 kDa apo A-I-like protein (ALP) that results from alternative splicing of the apo A-I primary transcript.
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PMID:Human placental tissue expresses a novel 22.7 kDa apolipoprotein A-I-like protein. 865 39