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)

The DNA homology relationships of 25 micrococci (15 strains of Micrococcus, eight strains of Sarcina and two strains of Staphylococcus) were studied by the deoxyribonucleic acid hybridization method using nuclease S1, an endonuclease specific for single-stranded DNA molecules. Nineteen of the strains were classified into three groups. Group I contained Micrococcus lysodeikticus IAMI056, M. luteus IAMI1010, M. flavus IAMI2005 and IAMI2006, Sarcina flava IAMI2007 and IAMI1006. S. subflava IAMI2009, S. lutea ATCC381, and ATCC382, and M. luteus IAMI1006. Group II contained M. roseus IAMI315, ATCC412, ATCC185 and IAMI295. Group III contained S. lutea IAMI099, IFO3232 and ATCC383, M. varians ATCC399 and Staphylococcus lactis ATCC15306. Micrococcus luteus IAMI097, M. varians ATCC19099 and ATCC19100, M. conglomeratus IAMI459 and IAMI470, and St. aureus IAMI011 could not be assigned to any of the three groups. The grouping corresponds to that derived from the results of differential lysis by lysozyme, 'lytic enzyme 2' from Cytophaga sp., or Streptomyces albus G enzyme; and to types of peptidoglycan in the cell walls and genetic transformation. The usefulness of classification based on sensitivity to various lytic enzymes was demonstrated. Group I probably coincides with M. luteus of Bergey's Manual of Determinative Bacteriology (1974), and groups II and III with M. roseus and M. varians respectively.
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PMID:Classification of micrococci on the basis of deoxyribonucleic acid homology. 18 Feb 38

Simian virus 40 (SV40) DNA I was transcribed with Escherichia coli RNA polymerase in the presence of gamma-32P-labeled ribonucleoside triphosphates in order to investigate the specificity of initiation of in vitro transcription. ATP and GTP served as predominant initiating nucleotides, the former being incorporated about twice as much as the latter. Cleavage of [gamma-32P]ATP-labeled SV40 complementary RNA (cRNA) with T1 RNase followed by homochromatographic analysis of the resultant 5' initiation fragments revealed the presence of four specific initiation fragments 6 to 9 nucleotides in length, designated AI, AII, AIIIa, and AIIIb. By means of hybridization of [gamma-32P]ATP-labeled SV40 cRNA to DNA from specific adenovirus 2-SV40 hybrids and specific restriction endonuclease fragments of SV40 DNA before chromatographic analysis, it was possible to identify and determine approximate localizations of five [gamma-32P]ATP initiation sites on the SV40 genome: one in Hin-G close to the Hin-G-B junction, giving rise to the AII fragment, two in the overalpping fragment Hin-A-Hae-A,giving rise to AI and AIII fragments, and two in the fragment Hin-A-Hae-E, also giving rise to AI and AIII fragments. All five sites either fall within or lie near regions of the genome that are cleaved by S1 nuclease and subject to partial alkaline denaturation. These five sites lie on the minus strand of SV40 DNA and initiate RNAs that are copied in a leftward direction. Cleavage of [gamma-32P]GTP-labeled cRNA with pancreatic RNase liberated three major 5' initiation fragments of short length, GI, GII, and GIII, suggesting the presence of three principal GTP initiation sites.
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PMID:Specificity of initiation of transcription of simian virus 40 DNA I by Escherichia coli RNA polymerase: identification and localization of five sites for initiation with [gamma-32P]ATP. 19 61

Mutants of simian virus 40 (SV40), with deletions ranging in size from fewer than 3 to 750 base pairs located throughout the SV40 genome, were obtained by infecting CV-1P cells with linear SV40 DNA and DNA of an appropriate helper virus. The linear DNA was obtained by complete cleavage of closed circular DNA with Hae II or Bam HI endonuclease or partial cleavage with either Hae III endonuclease or nuclease S1, followed, in some cases, by mild digestion with phage lambda 5' -exonuclease. The following mutants with deletions in the late region of the SV40 genome were obtained and characterized. Ten, containing deletions at the Hae II endonuclease site (map location 0.83), define a new genetic complementation group, E, grow extremely slowly without helper virus, and cause alterations only in VP2. Two mutants with deletions in the region 0.92 to 0.945 affect both VP2 and VP3, demonstrating that VP3 shares sequences with the C-terminal portion of VP2. The mutant with a deletion at 0.93 is the first deletion mutant in the D complementation group and is also temperature sensitive; the mutant with a deletion at 0.94 is viable and grows normally. Three mutants with deletions at the EcoRI endonuclease site (0/1.0) and eleven with deletions at the BamHI endonuclease site (0.15) fall into the B/C complementation group. Six additional mutants with deletions at the BamHI endonuclease site are viable, growing more slowly than wild type. VP1 is the only polypeptide affected by mutants in the B/C group. A mutant with a deletion of the region 0.72 to 0.80 has a polar effect, failing to express the E, D, and B/C genes. Mutants with deletions in the early region (0.67 counterclockwise to 0.17) at 0.66 to 0.59, 0.48, 0.47, 0.33, and 0.285 to 0.205 are all members of the A complementation group. Thus, the A gene is the only viral gene in the early region whose expression is necessary for productive infection of permissive cells. Since mutants with deletions in the region 0.59 to 0.54 are viable, two separate regions are essential for expression of the gene A function: 0.66 to 0.59 and 0.54 to 0.21. Mutants with deletions at 0.21 and 0.18 are viable. Approximate map locations of SV40 genes and possible models for their regulation are discussed.
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PMID:Physical and genetic characterization of deletion mutants of simian virus 40 constructed in vitro. 19 79

Circular viral DNA intermediates obtained from the quail tumor line, QT6, at 1 day after infection, were opened at one specific location by the single-strand specific nuclease, S1, of Aspergillus oryzae. This site was no longer accessible to the S1 nuclease when circles were first opened at another location with a restriction endonuclease.
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PMID:Specific site of action for single-strand specific nuclease on the double-stranded circular DNA intermediates of an avian RNA tumor virus. 21 77

Mutants of polyoma virus with deletions as large as 90 base pairs were isolated by selecting spontaneously arising genomes resistant to endonuclease HaeII or by treating HaeII- or BglI- cleaved linear DNAs with S1 nuclease and exonuclease III. All of the mutants were viable and, therefore, defined a nonessential region in the polyoma genome between the origin of DNA replication and the initiation codon for translation of early proteins. Several mutants with large deletions had altered growth properties, giving smaller plaques and lower virus yields than the parental wild-type virus. These viruses may lack sites that are important for DNA replication or for transcription and translation of early mRNA's. All of the mutants tested could transform BHK-21 cells to anchorage independence.
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PMID:Deletion mutants of polyoma virus defining a nonessential region between the origin of replication and the initiation codon for early proteins. 22 76

Superhelical covalently closed circular replicative form DNA (RF I) of coliphage M13 appears as a relaxed molecule that has a base-unpaired region in the form of a bubble (100 to 200 base pairs long) seen in electron micrographs when spread in the presence of formaldehyde and formamide or after pretreatment with glyoxal. S1 endonuclease, specific for single-stranded DNA, converts superhelical M13 RF I DNA, but not nonsuperhelical M13 RF I to a significant extent, into unit-length linear molecules by sequential nicking of two strands. The locations of S1 nuclease-susceptible sites and glyoxal-fixed base-unpaired regions were both related to the five A-T-rich regions in M13 RF DNA. While S1 nuclease does not show preference for any of these sites, glyoxal-fixed bubbles occur predominantly at the major A-T-rich region in M13 RF DNA.
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PMID:Base-unpaired regions in supercoiled replicative form DNA of coliphage M13. 32 5

Treatment of gently prepared lysates of Escherichia coli with single-strand-specific endonuclease (SI or from mung beans) results in the release of about 90% of the DNA from membranes, as determined by the M band technique. The released DNA has an average molecular weight of about 1.2 X 10(8). Data obtained with endonuclease S1 fit a mathematical model in which substrate sites are at or near membrane attachment sites. Data obtained with pancreatic deoxyribonuclease or x-rays fit a model for double-strand breaks at random sites along the DNA. Fitting data to these models, we estimate that there are 18+/-5 membrane attachment sites. The DNA remaining after S1 nuclease treatment is enriched for the region near the origin of chromosome replication. Therefore, attachment at this region near the origin of chromosome replication. Therefore, attachment at this region appears to be chemically different from that at the other sites along the DNA.
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PMID:Release of Escherichia coli DNA from membrane complexes by single-strand endonucleases. 33 16

We have employed S1 nuclease to probe the structure of an intermediate in tRNA biosynthesis available only in radiochemical purity. The dimeric precursor to tRNAGln and tRNALeu from bacteriophage T4 was digested with the single-strand specific nuclease, and the products of the reaction were compared with the S1 digestion products of the mature cognate tRNA'S. Quantitation and sequence analysis of the products revealed that the location and accessibility of S1 cleavage sites in the precursor were substantially identical with those in the mature forms. Based on these conclusions, it is argued that the dimer is comprised of two domains in which the specific features of both secondary and tertiary conformation closely resemble those found in the mature molecules; at the same time we noted small but apparently significant differences in certain regions of the molecule which may reflect signals for various maturation events. Finally, we have determined that the sites of precursor cleavage by RNase P, the endonuclease which generates the mature 5' termini of these tRNAs, were completely inaccessible to S1 digestion.
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PMID:S1 nuclease as a probe for the conformation of a dimeric tRNA precursor. 36 98

We present a method, utilizing a combination of restriction endonuclease cleavage and digestion with Escherichia coli exonuclease III and Aspergillus orizae nuclease S1, that allows us to position a restriction fragment bearing the promoter of the lacZ gene of E. coli at virtually any distance in front of any cloned gene. In particular, we have used this method to examine the effect on protein production of gene-promoter separation for the cro gene of phage lambda and to produce plasmids that, upon transformation into appropriate E. coli hosts, direct the synthesis of up to 190,000 cro protein monomers per cell.
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PMID:A general method for maximizing the expression of a cloned gene. 37 Aug 36

Synthetic double-stranded DNAs (sDNAs) were prepared from sheep globin mRNA templates isolated from reticulocytes producing either hemoglobin B (HbB) (alpha 2 beta B2), HbC (alpha 2 beta C2), or HbF (alpha 2 gamma 2). These DNAs were inserted into the Eco RI site of plasmid pMB9 by the homopolymer tailing method and used to transform Escherichia coli X1776 to tetracycline resistance. Recombinant clones were identified by colony hybridization and further characterized by molecular hybridization and restriction endonuclease analysis. All plasmids analyzed thus far contained either beta- or gamma-globin DNA sequences. Moreover, sDNAs used for cloning yielded restriction endonuclease fragments consistent with the presence of predominantly beta- or gamma-sDNA, indicating that formation of double-stranded alpha-sDNA proceeds much less efficiently under our conditions than the formation of non-alpha-sDNAs. Three recombinant plasmids, pS beta B2, pS beta C69, and pS gamma 56, were selected for detailed study. These were shown to contain, respectively, beta B-, beta C-, and gamma-DNA sequences by molecular hybridization and by protection of the appropriate cDNAs from S1 nuclease digestion. Each contained all of the restriction endonuclease sites defined for the synthetic sDNAs and protected at least 90% of the sequence length of homologous cDNA. Restriction endonuclease maps of the beta B- and beta C-globin genes were identical at all 12 sites that were mapped, whereas four differences were identified in the gamma gene compared to the two others; three of these corresponded to differences in amino acid sequence of the globins. A method was developed to isolate the anti-mRNA strand of the insert for use as a specific molecular hybridization probe analogous to complementary DNA.
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PMID:Hemoglobin switching in sheep. Synthesis, cloning, and characterization of DNA sequences coding for the beta B, beta C, and gamma-globin mRNAs. 37 94


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