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:3.1.30.1 (S1 nuclease)
3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous work has shown that growth hormone-releasing factor (GRF) stimulates cGMP production and somatostatin [somatotropin (growth hormone)-release-inhibiting factor, SRIF] release without altering cAMP accumulation by fragments of median eminence incubated in vitro. Therefore, this study was undertaken to evaluate the effect of GRF and cGMP on SRIF mRNA and SRIF release in the periventricular nuclei of male rats in vitro. SRIF mRNA levels were determined in explants of periventricular nuclei incubated for 6 hr in Waymouth's medium in the presence of various substances. Steady-state levels of SRIF mRNA were measured by an S1 nuclease protection assay using a 32P-labeled rat SRIF RNA probe. SRIF release and cGMP formation were measured at 30 min and 6 hr by RIA. SRIF mRNA levels and SRIF release were significantly (P < 0.025) increased (approximately 2-fold) by 1 microM dibutyryl cGMP, whereas sodium butyrate had no effect. This augmentation was not influenced by cycloheximide, an inhibitor of protein synthesis. Sodium nitroprusside (10 microM), an activator of the guanylate cyclase pathway via its release of nitric oxide, augmented (P < 0.001) SRIF mRNA levels and significantly increased (P < 0.05) SRIF release. GRF (1 nM) increased SRIF mRNA (P < 0.001) and stimulated the release of SRIF at 30 min (P < 0.05) and 6 hr (P < 0.01). This stimulation was abolished by 10 microM NG-monomethyl-L-arginine (L-NMMA), a specific inhibitor of nitric oxide synthase, but not by NG-monomethyl-D-arginine (D-NMMA, the inactive isomer). GRF also increased cGMP formation. This effect was completely blocked by incubation with L-NMMA but not D-NMMA. These results indicate that GRF releases nitric oxide. The nitric oxide diffuses to the adjacent SRIF neurons, where it activates guanylate cyclase, leading to increased formation of cGMP. This cGMP increases SRIF mRNA and SRIF release in the periventricular nuclei of male rats.
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PMID:Growth hormone-releasing factor increases somatostatin release and mRNA levels in the rat periventricular nucleus via nitric oxide by activation of guanylate cyclase. 790 58

Double-stranded RNA bands were detected electrophoretically in about 7% of natural isolates and in 13 of 51 collection strains belonging in section Nigri of the genus Aspergillus. The identity of these bands was proved by S1 nuclease and RNase treatment. Most of the virus-containing natural isolates came from Indonesia. Electron microscopic examination of the strains revealed the presence of virus-like particles in the mycelia of the strains examined. All of the virus-like particles were isometric and their size was around 30-35 nm, while some Indonesian isolates also contained virus-like particles in the size range 23-25 nm. It was possible to cure some of these strains of virus-like particles by mutagenic treatment. The four strains tested lost their virus-like particles and also their 'arginine-proline leaky' phenotype and became prototrophic. Virus transfer was possible among these four strains by protoplast fusion. It also proved possible to transfer mycoviruses into a more distantly related Aspergillus tubingensis strain by prolonged incubation of the polyethylene glycol treated protoplasts in osmotically stabilized medium. In spite of the finding that all Aspergillus foetidus and both Aspergillus heteromorphus strains examined contained double-stranded RNA segments and virus-like particles, no phenotypes related to the presence of these VLPs have been observed so far.
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PMID:Double-stranded RNA mycoviruses in section Nigri of the Aspergillus genus. 803 55

The carAB operons from Pseudomonas aeruginosa PAO1 and Pseudomonas stutzeri JM300 were characterized by Southern and DNA sequence analyses. The results show that the previously reported sequence for carA (S. C. Wong and A. T. Abdelal, J. Bacteriol. 172:630-642, 1990) is derived from P. stutzeri and not P. aeruginosa, as originally reported. Therefore, the amino-terminal sequence of the purified carA product is identical to that derived from the nucleotide sequence in both organisms, P. stutzeri having four additional amino acids. The results also show that while carA and carB are contiguous in P. stutzeri, as is the case in other bacteria, they are surprisingly separated by an open reading frame (ORF) of 216 amino acids in P. aeruginosa. S1 nuclease mapping experiments with RNA extracted under a variety of growth conditions, as well as experiments using different lacZ fusions, indicate that the carA-ORF-carB operon of P. aeruginosa is transcribed from a single promoter. Moreover, these experiments demonstrate that expression of this single transcript is controlled by both arginine and pyrimidines and that variation in arginine levels specifically modulates transcriptional initiation, while pyrimidine regulation is exerted subsequent to transcriptional initiation. Modification of a rho-independent terminator-like structure, which is present upstream of carA in P. aeruginosa, removed all transcriptional sensitivity of a carA::lacZ fusion to pyrimidines. This result, when coupled with the finding that translation of an 18-amino-acid leader polypeptide (associated with this putative rho-independent terminator), is inversely proportional to pyrimidine concentration in the cell, strongly suggests that regulation of carA by pyrimidines is mediated through an attenuation-type mechanism in P. aeruginosa.
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PMID:Structure and regulation of the carAB operon in Pseudomonas aeruginosa and Pseudomonas stutzeri: no untranslated region exists. 816 1

Structure and expression of the gene for a larval cuticle protein of the silkworm, Bombyx mori were studied. A major cuticle protein, termed 'LCP30' was purified from the urea extract of integuments of the fifth (final) instar larvae. Immunoblot analysis by use of the anti-LCP30 antibody revealed that LCP30 begins to accumulate in larvae as early as 10 h after hatch and is present throughout the larval stages. The LCP30 epitope is also detectable in the adult abdominal integument but is absent from pupal integument and adult wing. Screening of an epidermal cDNA expression library with the antibody probe yielded a cDNA clone for LCP30. Primary structure deduced from the cDNA sequence showed that LCP30 bears an arginine-glycine-aspartate (RGD) sequence. The region around this domain exhibits striking similarity with the amino acid sequences found in vertebrate collagens. The genomic DNA clone coding for LCP30 was isolated by screening a B. mori gene library with the LCP30 cDNA probe. The gene consists of five exons interspersed by four introns spanning over 2.7 kb region of chromosomal DNA. The LCP30 mRNA is detectable at high levels at larval intermolt stages, gradually declines after the fourth molt and totally disappears at mid-fifth larval instar, indicating that the expression of LCP30 gene is regulated in a stage-specific fashion in the epidermal cells. Topical application of a juvenile hormone analogue (methoprene) to the fifth instar larvae followed by RNA blot and S1 nuclease mapping analyses of the epidermal RNA proved that juvenile hormone activates transcription of the LCP30 gene.
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PMID:Structure and developmental expression of a larval cuticle protein gene of the silkworm, Bombyx mori. 819 66

A homolog of the transcriptional elongation factor, GreA, was identified in Pseudomonas aeruginosa PAO1. The deduced amino acid sequence for GreA from this organism exhibits 65.2% identity to its counterpart in Escherichia coli K-12. The nucleotide sequence of greA from P. aeruginosa overlaps by four bases the 3' terminus of carB which encodes the large subunit of carbamoylphosphate synthetase. S1 nuclease experiments showed that level of the greA transcript is elevated approximately 10-fold under conditions of pyrimidine limitation, consistent with the conclusion that transcription is initiated from the previously identified pyrimidine-sensitive promoter upstream of the carA-orf-carB-greA operon. Transcriptional fusion experiments showed the presence of an additional weak promoter within the carB sequence. A greA insertional mutant of Pseudomonas aerugionsa was constructed by gene replacement. The mutant derivative grew well in rich medium but did not grow in minimal medium supplemented by arginine and nucleosides. The greA phenotype was suppressed by secondary mutations at a relatively high rate, consistent with the notion of an important physiological role for GreA.
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PMID:Identification of greA encoding a transcriptional elongation factor as a member of the carA-orf-carB-greA operon in Pseudomonas aeruginosa PAO1. 913 26

Pseudomonas aeruginosa ArgR, a regulatory protein that plays a major role in the control of certain biosynthetic and catabolic arginine genes, was purified to homogeneity. ArgR was shown to be a dimer of two equal subunits, each with a molecular mass of 37,000 Da. Determination of the amino-terminal amino acid sequence showed it to be identical to that predicted from the derived sequence for the argR gene. DNase I footprinting showed that ArgR protects a region of 45 to 47 bp that overlaps the promoters for the biosynthetic car and argF operons, indicating that ArgR exerts its negative control on the expression of these operons by steric hindrance. Studies were also carried out with the aru operon, which encodes enzymes of the catabolic arginine succinyl-transferase pathway. Quantitative S1 nuclease experiments showed that expression of the first gene in this operon, aruC, is initiated from an arginine-inducible promoter. Studies with an aruC::lacZ fusion showed that this promoter is under the control of ArgR. DNase I experiments indicated that ArgR protects two 45-bp binding sites upstream of aruC; the 3' terminus for the downstream binding site overlaps the -35 region for the identified promoter. Gel retardation experiments yielded apparent dissociation constants of 2.5 x 10(-11), 4.2 x 10(-12), and 7.2 x 10(-11) M for carA, argF, and aruC operators, respectively. Premethylation interference and depurination experiments with the car and argF operators identified a common sequence, 5'-TGTCGC-3', which may be important for ArgR binding. Alignment of ArgR binding sites reveals that the ArgR binding site consists of two half-sites, in a direct repeat arrangement, with the consensus sequence TGTCGCN8AAN5.
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PMID:Purification and characterization of an arginine regulatory protein, ArgR, from Pseudomonas aeruginosa and its interactions with the control regions for the car, argF, and aru operons. 928 81

The complete nucleotide sequence for the aot operon of Pseudomonas aeruginosa PAO1 was determined. This operon contains six open reading frames. The derived sequences for four of these, aotJ, aotQ, aotM, and aotP, show high similarity to those of components of the periplasmic binding protein-dependent ABC (ATP binding cassette) transporters of enteric bacteria. Transport studies with deletion derivatives established that these four genes function in arginine-inducible uptake of arginine and ornithine but not lysine. The aotO gene, which encodes a polypeptide with no significant similarity to any known proteins, is not essential for arginine and ornithine uptake. The sixth and terminal gene in the operon encodes ArgR, which has been recently shown to function in regulation of arginine metabolism. Studies with an aotJ::lacZ translational fusion showed that expression of the aot operon is strongly induced by arginine and that this effect is mediated by ArgR. S1 nuclease and primer extension experiments showed the presence of two promoters, P1 and P2. The downstream promoter, P2, is induced by arginine and appears to be subject to carbon catabolite repression. The upstream promoter, P1, is induced by glutamate. Footprinting experiments established the presence of a 44-bp ArgR binding site that overlaps the -35 region for P2, as was shown to be the case for the arginine-inducible aru promoter, and the -10 region for P1, as was shown to be the case for arginine-repressible operons in P. aeruginosa. Sequence alignment confirms the architecture and the consensus sequence of the ArgR binding sites, as was previously reported.
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PMID:Molecular characterization and regulation of an operon encoding a system for transport of arginine and ornithine and the ArgR regulatory protein in Pseudomonas aeruginosa. 979 Nov 3

A cluster of genes argCJBDRGH containing most of the arginine biosynthesis genes has been found in Streptomyces clavuligerus after sequencing a 8.3 kb DNA region containing overlapping sequences of two DNA fragments known to contain arginine biosynthesis genes. Subcloning, complementation of E. coli arginine auxotrophic strains and enzymatic assays confirmed the identity of each gene. S1 nuclease mapping studies and Northern hybridization analysis revealed the formation of two large transcripts corresponding to argCJBDR and argGH. The amount of each of these mRNAs is 10 to 44 times higher in a S. clavuligerus argR-disrupted mutant than in the wild type confirming the existence of an ArgR-mediated control of arginine biosynthesis gene expression. A low level constitutive monocistronic transcript of argR was observed in S. clavuligerus cells. Most of the argGH transcript initiating at an adenine 29 nt upstream of the argG initiation codon appears to stop at a termination stem and loop structure present downstream of the argG gene.
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PMID:Characterization and expression of the arginine biosynthesis gene cluster of Streptomyces clavuligerus. 1107 30

Citrullinaemia is an inborn error of metabolism resulting from a deficiency of argininosuccinate synthetase. Previous studies of RNA of argininosuccinate synthetase of citrullinaemia patients using S1 nuclease analysis have identified a class of so-called RNA-negative alleles in which no stable mRNA can be detected. To investigate the nature of mutation responsible for such a phenotype, a compound heterozygous citrullinaemia carrying an RNA-negative allele and an allele with a 3' splice site mutation in intron 6 (IVS6-2A>G) was analysed. Using sequences of a DNA polymorphism and the IVS6-2A>G mutation as markers, approximately equal amounts of pre-mRNAs from allelic genes were detected suggesting that RNA-negative phenotype could not be the result of defect in transcription initiation. A C-to-T transition converting the CGA arginine codon at residue 279 to a TGA termination codon (R279X) was identified by cDNA sequencing. No accumulation of partially spliced pre-mRNAs containing introns immediately upstream and downstream of the nonsense mutation was observed. In addition, no mRNA species of abnormal size was detected when cDNA from the RNA-negative allele was analysed. Hence, there is no indication of nonsense-associated altered splicing (NAS). The most likely event responsible for the RNA-negative phenotype appears to be nonsense-mediated mRNA decay (NMD).
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PMID:A nonsense mutation is responsible for the RNA-negative phenotype in human citrullinaemia. 1157 57

A nuclear gene AB80 has been isolated from a phage lambda Charon 4 library of pea DNA. The sequence of the gene has been determined and it has been shown to contain an uninterrupted reading frame of 269 amino acids, corresponding to a precursor to a constituent polypeptide of the light-harvesting chlorophyll a/b-protein complex. Primer extension and S1 nuclease studies defined a cap site for AB80. The first methionine codon 3' from this site is 69 nucleotides away and is the initiating codon of the open reading frame. A "TATA" sequence occurs 31 nucleotides 5' from the cap site. A second TATA sequence is found 7 nucleotides on the 5' side of the initiating methionine codon and the sequences surrounding this TATA sequence are strikingly similar to those surrounding the first TATA sequence. The mature polypeptide encoded by AB80 differs by 5 amino acids from the polypeptide corresponding to a previously characterized cDNA sequence pAB96. This result is indicative of heterogeneity within the constituent polypeptides of the light-harvesting chlorophyll a/b-protein complex. The sequence Arg-Lys-Ser-Ala-Thr-Thr-Lys-Lys occurs at, or near, the NH(2)-terminus of the mature polypeptide encoded by AB80. This basic peptide is of interest because of its apparent involvement in changes in excitation-energy distribution in chloroplast membranes. Some general similarities, but no extensive sequence homology, is found on comparing the transit sequence for the precursor to the chlorophyll a/b-binding polypeptide with the transit sequences previously determined for the precursors to the small subunit of ribulose-1,5-bisphosphate carboxylase.
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PMID:Structure and expression of a pea nuclear gene encoding a chlorophyll a/b-binding polypeptide. 1659 61


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