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:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasmid pSL103 was previously constructed by cloning a Trp fragment (approximately 2.3 X 10(6) daltons) from restriction endonuclease EcoRI-digested chromosome DNA of Bacillus pumilus using the neomycin-resistance plasmid pUB110 (approximately 2.8 X 10(6) daltons) as vector and B. subtilis as transformation recipient. In the present study the EcoRI Trp fragment from pSL103 was transferred in vitro to EcoRI fragments of the Bacillus plasmid pPL576 to determine the ability of the plasmid fragments to replicate in B. subtilis. Endonuclease EcoRI digestion of pPL576 (approximately 28 X 10(6) daltons) generated three fragments having molecular weights of about 13 X 13(6) (the A fragment), 9.5 X 10(6) (B fragment, and 6.5 X 10(6) (C fragment). Trp derivatives of pPL576 fragments capable of autonomous replication in B. subtilis contained the B fragment (e.g., pSL107) or both the B and C fragments (e.g., pSL108). Accordingly, the B fragment of pPL576 contains information essential for autonomous replication. pSL107 and pSL108 are compatible with pUB110. Constructed derivatives of the compatible plasmids pPL576 and pUB110, harboring genetically distinguishable EcoRI-generated Trp fragments cloned from the DNA of a B. pumilus strain, exhibited relatively high frequency recombination for a trpC marker when the plasmid pairs were present in a recombination-proficient strain of B. subtilis. No recombination was detected when the host carried the chromosome mutation recE4. Therefore, the recE4 mutation suppresses recombination between compatible plasmids that contain homologous segments.
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PMID:Recombination between compatible plasmids containing homologous segments requires the Bacillus subtilis recE gene product. 9 91

Transcribing Bacillus cereus DNA was visualized by means of autoradiography of electrophoretically separated EcoRI restriction endonuclease DNA fragments hybridizing 32P-labeled RNA. Hybridization of RNA of dormant spores, vegetative cells, and outgrowing spores indicates the following. (i) A large fraction of the nonribosomal RNA in dormant spores is transcribed at a limited number of regions on the bacterial chromosome. (ii) After induction of spore germination, transcription activity is not limited to a single short region on the chromosome, but rather is distributed along the chromosome. The DNA/RNA hybridization technique has been used to identify restriction endonuclease DNA fragments homologous to RNA species that are present in dormant spores but absent from vegetative cells, RNA species that are synthesized immediately after germination induction and are present at a relatively low concentration in vegetative cells, and RNA species that are transcribed at a late stage of outgrowth but are absent or present at low concentration at an early stage of outgrowth.
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PMID:Hybridization analysis of restriction endonuclease DNA fragments of Bacillus cereus transcribed during spore outgrowth. 9 96

The properties of Dm 225 DNA, a fragment of D.melanogaster genome 2.9 kb in length excised by EcoRI endonuclease and cloned in the lambda gt phage or pMB9 plasmid, are described. The DNA hybridizes to a significant portion (0.8%) of total polysomal poly(A)(+)RNA (mRNA). The size of the hybridizing mRNA is about 2.3 kb (19S); it is present in the fraction of heavy polysomes. Dm 225 DNA fragments obtained with the aid of Hae III endonuclease have been mapped. mRNA hybridizes with all the fragments. In one of the end fragments, the 3'-end of mRNA has been localized and thus the direction of transcription determined. About 250 copies of the gene Dm 225 are present in the haploid genome of D.melanogaster, and all of them have the same size upon restriction with EcoRI endonuclease. On the other hand, the sequences of the genome adjacent to Dm 225 DNA are different and may vary from one cell line to another as evidenced by experiments in which the D.melanogaster DNA was restricted by Hind III endonuclease. In combination with in situ hybridization data /1,2/ the results obtained in this paper demonstrate that the structural gene present in Dm 225 DNA is a representative of a multiple gene family dispersed throughout the whole genome of D.melanogaster.Images
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PMID:The properties of gene Dm 225, a representative of dispersed repetitive genes in Drosophila melanogaster. 9 35

A comparative study has been made on the kinetoplast DNA (kDNA) from I in culture epimastigote, blood trypomastigote and intracellular amastigote stages of Trypanosoma cruzi. The basic properties of the kDNA in all 3 forms were identical. Thus the DNA was in the form of networks of density 1.698-9 g/cm3 and with sedimentation coefficients (S20w) of approximately 5500, the networks being composed of large complexes of minicircular and apparently linear molecules, the former having contour lengths of 0.45 MICROMETer. Several differences were noted. The ultrastructural arrangement of the kDNA in the kinetoplast of the blood stage consisted of three to four double rows of DNA as compared to one double layered row in the other two stages. There was proportionately more kDNA in the blood stages, suggesting that, since the networks have apparently the same size (see above), more than one is present. DNA loops situated at the periphery of the kDNA networks were observed in higher proportion in blood and intracellular forms. Dimeric and oligomeric circles were present in the kDNA of the blood and intracellular stages in much greater proportion than in culture epimastigote stages. Few large circular molecules, heterogeneous in size, were also observed in intracellular blood stages. There were some differences, mainly quantitative, in the gel electrophoresis patterns after endonuclease digestion.
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PMID:Comparative study of kinetoplast DNA in culture, blood and intracellular forms of Trypanosoma cruzi. 9 79

Genes encoding thymidylate synthetase from Bacillus subtilis bacteriophages were cloned in Escherichia coli. Chimeric plasmids pCD1 and pCD3 were constructed from site-specific endonuclease digests of bacteriophage phi3T DNA cloned in pMB9 in E. coli. Similar cloning techniques with bacteriophage beta22 DNA yielded chimeric plasmids pCD4, pCD5, and pCD6. Endonuclease digests of DNA from pCD1 and pCD3 propagated in E. coli or from DNA isolated from bacteriophage phi3T propagated in B. subtilis transformed B. subtilis from Thy- to Thy+. Intact DNA from bacteriophage beta22, endonuclease digests of beta22 DNA, and a chimeric plasmid (pCD5) composed only of the thybeta22 gene and pMB9 did not transform B. subtilis from Thy- to Thy+ even though pCD5 could transform Thy- E. coli to Thy+. However, if the thybeta22 fragment from pCD5 was introduced into another chimeric plasmid, pCD2, that contains a region of homology to the chromosome of B. subtilis in addition to pMB9, transformation of Thy- clones of B. subtilis was possible. Furthermore, Southern hybridization analyses of the digests of chromosomal DNA from the Thy+ transformants established that the entire chimeric plasmid was incorporated into the chromosome of B. subtilis. Treatment of these plasmids with site-specific endonucleases abolished transformation. These results indicated that the entire chimeric plasmid can be incorporated into the chromosome of B. subtilis by a Campbell-like model. Therefore, an additional mechanism for transformation exists whereby plasmids can be integrated if sufficient chromosomal homology is maintained.
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PMID:Mechanism of integrating foreign DNA during transformation of Bacillus subtilis. 9 40

The yeast Kluyveromyces lactis synthesizes a beta-galactosidase (EC 3.2.1.32) which is inducible by lactose. We have isolated the gene that codes for this enzyme using recombinant DNA techniques. K. lactis DNA was partially digested with the restriction endonuclease Eco R1 and joined to Eco R1-digested pBR322 plasmid DNA using DNA ligase. ligase. A lac-mutant of Escherichia coli lacking the structural gene for beta-galactosidase was transformed with ligated DNA. Three lac+ transformants containing recombinant plasmids were selected. Two of the plasmids (pK15 and pK17) contain four Eco R1-K. lactis DNA fragments having molecular weights of 2.2, 1.4, 0.55 and 0.5 x 10(6) daltons. The other plasmid (pK16) lacks the smallest fragment. E. coli carrying any of these plasmids produce beta-galactosidase activity that has a sedimentation coefficient and immunological determinants that are nearly identical to K. lactis beta-galactosidase and distinctly different from E. coli beta-galactosidase. DNA-DNA hybridization studies show that the four Eco R1 fragments in pK15 hybridize to K. lactis but not to E. coli DNA.
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PMID:Molecular cloning and expression in E. coli of a yeast gene coding for beta-galactosidase. 10 Feb 26

Cleavage maps of the three similar Bacillus subtilis temperate bacteriophages, phi105, rho10, and rho14, were constructed by partial digestion analysis utilizing the restriction endonuclease EcoRI. Comparison of the topography of these maps indicates that all phage DNAs posses cohesive ends and a number of EcoRI restriction sites; the fragments are conserved, and the estimated base substitution/nucleotide divergence between these phages is 0.03 to 0.07 based on conserved fragments or between 0.03 and 0.11 based on conserved cleavage sites. These lines of evidence indicate that phi105, rho10, and rho14 are closely related. Double-enzyme digestion analysis reveals that rho14 DNA has unique SalGI and BglII restriction sites and phi105 DNA has a unique SalGI restriction site, making these phages possible cloning vectors for B. subtilis.
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PMID:Restriction endonuclease mapping of bacteriophage phi105 and closely related temperate Bacillus subtilis bacteriophages rho10 and rho14. 10 Jun 13

RNA transcription from defined regions of the Euglena gracilis chloroplast genome has been characterized by hybridization of total cell RNA to 3H-labeled chloroplast DNA restriction endonuclease fragments. Chloroplast DNA was digested into five fragments of 53, 35, 25, 10, and 6.9 kilobase pairs (kbp) with Pst1. The 53-kbp DNA was also subfractionated by BamHI digestion. The extent of transcription of the Pst1 fragments was found to be 30, 17, 15, 2.2, and 2.3 kb of RNA, respectively. The total amount of RNA transcription of 67 kb represents 26% to the double-strand information content of the genome. Transcribed regions are dispersed throughout the DNA. The RNA transcripts are present in two major abundance classes in the cell. High abundance transcripts of approximately 10(6) copies/cell were mapped in the rRNA gene region of the 53-kbp fragment and in the 35-kbp fragment. Low abundance transcripts of approximately 1000--4000 copies/cell were mapped in all five Pst fragments.
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PMID:Mapping of transcribed regions of Euglena gracilis chloroplast DNA. 10 Dec 38

Among 120 strains of gliding bacteria which were screened for restriction endonucleases, 27 were found positive. Additionally, three strains carried enzymes able to release the supercoiled state of closed circular DNA. By using a new rapid method, restriction endonuclease activity was released by stirring about 0.5 g of cells (fresh weight) in a motor-driven glass homogenizer in buffer containing Triton X-101, ethylenediaminetetraacetic acid, and mercaptoethanol. A yield from 60 to 80% of the total activity present in the cells was obtained with minimal destruction of the cells. The enzyme activity in the crude extract was measured semi-quantitatively by digestion of DNA and subsequent separation of the fragments on an agarose slab gel. The method appears to be generally applicable for the extraction of restriction endonucleases from gram-negative bacteria on an analytical scale and in a modified form for large-scale preparation of restriction enzymes.
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PMID:Restriction endonucleases: general survey procedure and survey of gliding bacteria. 10 30

The DNA polymerase induced by Bacillus subtilis bacteriophage PBS2 has a Stokes radius of 7.2 in buffers of high ioninc strength, suggesting a molecular weight in the range 145,000 to 195,000. The polypeptide bands observed on gel electrophoresis in dodecyl sulfate have apparent molecular weights of 78,000 and 69,000 (and possibly another 27,000) in equimolar amounts. In buffers of low ionic strength, the enzyme appears to form large aggregates and even precipitates, with about 90% loss of activity. A nuclease activity co-purifies with the PBS2 DNA polymerase and shows similar responses to changes in pH, MgCl2, N-ethylmaleimide, temperature, and dextran sulfate levels. The nuclease produces deoxyribonucleoside 5'monophosphates from denatured DNA containing thymine or uracil. No endonuclease activity is detectable on supercoiled DNA. The inhibition of nuclease activity by added deoxyribonucleoside triphosphates, the DNA-dependent turnover of triphosphates, to free monophosphates during DNA polymerization, the inhibition of nuclease activity by 3'-phosphates on the DNA template-primer, and the pattern of digestion of 5'-[32P]phosphate-labeled DNA all indicate that the PBS2 DNA polymerase-associated hydrolytic activity is a 3' leads to 5'-exonuclease.
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PMID:Characterization of the Bacillus subtilis bacteriophage PBS2-induced DNA polymerase and its associated exonuclease activity. 10 39


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