Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

ARGRII is one of the three regulatory genes controlling arginine metabolism in yeast. From a pool of hybrid plasmids carrying Sau3A fragments representing the entire yeast genome, a DNA fragment containing the regulatory gene ARGRII was cloned by complementation of an argRII- mutation, which prevents growth on ornithine as sole nitrogen source. Cells containing the cloned DNA regained the ability to repress the synthesis of anabolic enzymes and to induce the synthesis of the catabolic ones, when arginine is present. The 6.2 kb cloned DNA fragment encodes five transcripts (2.8 kb, 1.3 kb, 0.75 kb, 0.45 kb, 0.45 kb), which were located by S1 endonuclease mapping. By marker rescue the argRII- mutations were mapped in the DNA region coding for the 2.8 kb transcript, showing its importance in the control mechanism. Subcloning experiments confirm this result. However, at present the role of the 0.75 kb and 1.3 kb transcripts in the ARGR+ phenotype is unclear.
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PMID:Isolation and characterization of the yeast ARGRII gene involved in regulating both anabolism and catabolism of arginine. 388 75

In S. cerevisiae, the synthesis of ureaamidolyase is subject to at least two different forms of regulation: nitrogen catabolite repression and induction by allophanate. Two positive regulatory genes DURM and DURL are involved in the induction process. We have measured the levels of mRNA homologous to the DUR2,1 gene in conditions of ureaamidolyase induction and in regulatory mutants. The amounts of DUR2,1 enzyme and messengers are well coordinated; moreover, the half life of DUR2,1 messengers is identical in the presence or absence of inducer. These data suggest that the ureaamidolyase production is probably controlled at the level of transcription. From a pool of hybrid plasmids carrying Sau3A fragments representing the entire yeast genome, a 13 kb DNA fragment containing the regulatory gene DURM was cloned by complementation of a durM mutation which prevents the growth on allantoin as sole nitrogen source. Cells containing the cloned DNA recover the inducibility of ureaamidolyase by allophanate. Four RNA transcripts have homology to this 13 kb DNA fragment but the study of subcloned restriction endonuclease fragments allowed us to map the DURM regulatory gene within a 4 kilobase pair region. This fragment encodes a 1 kb transcript. The level of this RNA is the same in induced and non-induced cells.
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PMID:Regulation of ureaamidolyase synthesis in Saccharomyces cerevisiae, RNA analysis, and cloning of the positive regulatory gene DURM. 391 27

DNA fragments of defined sequence have been used to determine the sites of cleavage by gamma-endonuclease activity in extracts prepared from Micrococcus luteus. End-labeled DNA restriction fragments of pBR322 DNA that had been irradiated under nitrogen in the presence of potassium iodide or t-butanol were treated with M. luteus gamma endonuclease and analyzed on high resolution, denaturing, polyacrylamide gels. Gamma endonuclease was found to cleave irradiated DNA preferentially at the positions of cytosines and thymines. DNA cleavage occurred immediately to the 3' side of pyrimidines in irradiated DNA and resulted in fragments that terminate in a 5'-phosphoryl group. These studies indicate that both altered cytosines and thymines may be important DNA lesions requiring repair after exposure to gamma radiation.
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PMID:Sequence specificity of DNA cleavage by Micrococcus luteus gamma endonuclease. 398 67

The purpose of these experiments was to determine the role of double-strand breaks in chromosome aberration formations. Quiescent normal human fibroblasts were treated with 3 microM nitrogen mustard and then allowed to repair their DNA damage for 24 h prior to cell fusion and induction of premature chromosome condensation. The extent of chromosome damage was determined in the G1 prematurely condensed chromosomes (G1 PCC). The presence of cytosine arabinoside and hydroxyurea during the repair period in order to accumulate single-strand DNA breaks resulted in an increase in the chromosome-break frequency. Treatment of these repair-inhibited cells with single-strand-specific neurospora endonuclease during fusion to change single-strand lesions into double-strand breaks resulted in a doubling of the aberration frequency. These results support the notion that double-strand breaks are important in chromosome-aberration formation.
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PMID:Induction of chromosome damage by Neurospora endonuclease in repair-inhibited quiescent normal human fibroblasts. 609 3

The amidase genes of Pseudomonas aeruginosa were inserted into a lambda replacement vector following cleavage with the restriction endonuclease HindIII. The recombinant lambdaami was detected by enhanced growth of Escherichia coli around plaques of the recombinant phage on minimal medium containing acetamide as the nitrogen source. Low levels of amidase activity were detected in E. coli cultures infected with lambdaami and these were sufficient to allow growth with acetamide as nitrogen source. Lysis-defective derivatives of lambdaami were made by introducing Q-, S-, mutations. Cultures of E. coli infected with lambdaamiQ-S- synthesised amidase as the major protein. The amidase produced by these cultures was identical to that produced by PAC strains of P. aeruginosa in substrate specificty, thermal stability and immunological cross-reaction.
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PMID:The construction in vitro of derivatives of bacteriophage lambda carrying the amidase genes of Pseudomonas aeruginosa. 624 42

Bacteriophages of methanotrophic bacteria were isolated from 67 fish. Only two phages isolated from two fish species specifically lysed Methylocystis sp. and Flavobacterium gasotypicum. The phages lysing these species were designated 63-F and CMF-1-F, respectively. The isolated phages differed greatly in the fine structure of the virion, plaque morphology, spectrum of lytic action, serological properties, and UV sensitivity. At the same time, they had identical one-step growth characteristics: their latent period equalled 5 h, lysis time was 3 to 4 h, and burst size was about 240 virions. The phages had guanine- and cytosine-rich double-stranded DNAs consisting of common nitrogen bases. The molecular masses of the DNAs as determined by the sums of restriction endonuclease cleavage fragments were 28 X 10(6) daltons for phage 63-F and 31 X 10(6) daltons for phage CMF-1-F.
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PMID:Bacteriophages of methanotrophs isolated from fish. 641 69

A number of 2',5'-linked oligoadenylates and their analogues were prepared and evaluated for their ability to interact with the 5'-O- triphosphoadenylyl -(2'----5')-adenylyl-(2'----5')-adenosine (2-5A) dependent endoribonuclease of mouse L cells. The oligonucleotides were assayed for their ability to antagonize the action of 2-5A, to displace a radiolabeled probe from the 2-5A-dependent nuclease, or to inhibit translation in a cell-free system. These experiments demonstrated the following: (1) Three AMP residues in a 5'-phosphorylated oligonucleotide were needed for maximum interaction with the endonuclease, and higher oligomers (greater than or equal to 4 AMP residues) did not show significantly higher binding. (2) The third (2'-terminal) adenosine residue was required for optimal binding activity. (3) 5'-Phosphorylation of the oligonucleotide was necessary for maximum binding to the endonuclease, but the first (from the 5' terminus) internucleotide phosphate of higher unphosphorylated or core oligomers, such as A2'p5'A2'p5'A2'p5'A, may partly replace the requirement for a 5'-monophosphate moiety; in agreement with this, the 5'-methyl ester of 5'pA2'p5'A2'p5'A, i.e., Me-p5'A2'p5'A2'p5'A, was bound to the endonuclease as well as or better than the higher core oligomers but approximately 100 times more effectively than the trimer core, A2'p5'A2'p5'A. (4) Base-modified analogues, such as p5'C2'p5'C2'p5'C, p5'U2'p5'U2'p5'U, or p5'I2'p5'I2'p5'I, were at least 2000 times less effectively bound to the endonuclease than p5'A2'p5'A2'p5'A. (5) The triphosphate ppp5 'I2'p5'I2'p5'I was 10 000 times less active than 2-5A as an inhibitor of translation. These latter two points implied the critical role of the adenine N1-nitrogen and/or exocyclic amino group in the binding of 2-5A to the endonuclease.
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PMID:Oligonucleotide structural parameters that influence binding of 5'-O-triphosphoadenylyl-(2'----5')-adenylyl-(2'----5')-adenosine to the 5'-O-triphosphoadenylyl-(2'----5')-adenylyl-(2'----5')-adenosine dependent endoribonuclease: chain length, phosphorylation state, and heterocyclic base. 673 14

Bacteriophages of methanotrophic bacteria have been found in 16 out of 88 studied samples (underground waters, pond water, soil, gas and oil installation waters, fermentor cultural fluids, bacterial paste, and rumen of cattle) taken in different geographic zones of the Soviet Union. Altogether, 23 phage strains were isolated: 10 strains that specifically lysed only Methylosinus sporium strains, 2 strains that each lysed 1 of 5 Methylosinus trichosporium strains studied, and 11 strains that lysed Flavobacterium gasotypicum and, at the same time, 1 M. sporium strain. By fine structure, the phages were divided into two types (with very short or long noncontractile tails); by host range and serological properties, they fell into three types. One-step growth characteristics of the phages differed only slightly; the latent period varied from 6 to 8 h, the rise period varied from 4 to 6 h, and the average burst size was 100. All phages had guanine- and cytosine-rich double-stranded deoxyribonucleic acid consisting of common nitrogen bases. The molecular mass of the deoxyribonucleic acid as determined by restriction endonuclease analysis was 29.4 X 10(6) for M. sporium phages and 44 X 10(6) for F. gasotypicum phages. By all of the above-mentioned properties, all phages within each of the groups were completely identical to one another, but differed from phages of other groups. Bacteriophages lysing M. sporium and M. trichosporium GB2 were identical to phages M1 and M4, respectively, which were isolated earlier in the German Democratic Republic on the same methanotrophic species.
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PMID:Bacteriophages of methanotrophic bacteria. 677 62

Cloned nitrogen fixation (nif) genes from Klebsiella pneumoniae hybridize to DNA from 19 out of 19 widely divergent nitrogen-fixing bacterial strains but do not hybridize to DNA from 10 different non-nitrogen-fixing species. K. pneumoniae nif DNA fragments that hybridize to DNA from other species contain part of the three structural genes that code for nitrogenase polypeptides. We have utilized this homology to clone an EcoRI restriction endonuclease fragment from Rhizobium meliloti that hybridizes to the K. pneumoniae nif structural genes. Some of the species whose DNA hybridizes with K. pneumoniae nif DNA have been postulated to have diverged from K. pneumoniae 3 x 10(9) years ago. Nitrogenase genes are the only known example of such highly conserved prokaryotic translated genes. Nitrogenase genes are either extraordinarily conserved in evolution or have been exchanged between different nitrogen-fixing species relatively recently in evolutionary time.
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PMID:Interspecies homology of nitrogenase genes. 698 49

The changes in the molecular weight of DNA one-strand fragments were studied after a short-term incubation of 101/H and CBA mouse cells with embichin (nitrogen mustard). Unlike CBA mouse cells in which the repair of DNA lesions is completed after 24 hours, DNA in 101/H mouse cells was shown to be strongly fragmented. It is assumed that the deficiency of the repair of DNA lesions induced by embichin in 101H/ mouse cells is due to the deficiency of the last stage of excision repair, namely of the ligase reaction or to the uncoordinated pattern of the endonuclease and ligase reactions.
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PMID:[Repair of embichin-induced DNA damage in embryonal fibroblasts of 101/H and CBA mice]. 733 80


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