Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A restriction endonuclease analysis of the plasmids pSC101 and pMB9 has allowed a determination of the alterations that occurred in the tetracycline resistance locus during the construction of pMB9 from pSC101. The genes for four of the polypeptides involved in tetracycline resistance have been positioned on the restriction endonuclease map of pSC101.
Mol Gen Genet 1978 Sep 08
PMID:Restriction endonuclease mapping of pSC101 and pMB9. 71 15

The 30S nuclear RNP particles from rat liver have been shown to split the double-stranded- (ds) and single-stranded (ss) sequences of nuclear pre-mRNA. Experiments performed in vitro have demonstrated that 1) a 5'-exonuclease and an endonuclease specific for double-stranded pre-mRNA sequences exist in the 30S pre-mRNP particles; 2) in dsRNA monophosphorylated 5'-termini arose in the course of incubation with 30S RNP and most of the products remained double-stranded. The analysis of terminal pNp nucleotides revealed a relatively high ratio of pPyp in the cleaved dsRNA, whereas the nucleosides in 5'-terminal pNp of ssRNA showed nearly random distribution. Our results provide a possible explanation for the appearance of pNp termini during the processing of nuclear pre-mRNA of mammalian cells.
Mol Biol Rep 1978 Oct 16
PMID:Cleavage of pre-mRNA sequences by ribonucleases bound to nuclear RNP particles of rat liver. 73 82

Some aspects of DNA repair in several radiation-resistant and radiation-sensitive strains of Dictyostelium discoideum were investigated by using alkaline sucrose gradients to analyze for the production and resealing of single-strand breaks following irradiation with 254 nm UV. All radiation-resistant strains and all mutants assayed that are sensitive to both UV and 60Co gamma rays produced single-strand breaks in their nuclear DNA after a UV fluence of 15 M/m2. Mutants at the radC locus which are sensitive to UV but as resistant as their parental strains to 60Co gamma rays produced many fewer single-strand breaks in their DNA after irradiation with UV. Thus, the radC mutations alter a repair pathway specific for UV-induced DNA damage and presumably affect the activity of a UV-damage-specific endonuclease involved in excision repair. All radiation-resistant strains and all of our mutants sensitive to gamma rays rejoined much of their DNA during a three-hour post-UV-irradiation incubation, suggesting that these strains have at least a partially intact excision repair system.
Mol Gen Genet 1979 Jan 02
PMID:In vivo nicking and rejoining of nuclear DNA in ultraviolet-irradiated radiation-resistant and sensitive strains of Dictyostelium discoideum. 76 36

1. We have isolated large fragments of the mtDNA of the yeast Saccharomyces carlsbergensis and digested these with restriction endonucleases. The digestion products were separated by electrophoresis in agarose gels. 2. Endonucleases EcoRI, HindII + III, HpaI, HindIII and HapII yield 9, 11, 6, 0 and greater than 80 fragments, respectively. 3. By analysis of partial digestion products and by redigesting the fragments obtained with one endonuclease with a second, we have established the order of all EcoRI and HindII + III fragments. The map is circular and its contour length is 22.1 +/- 0.35 mum, in good agreement with earlier estimates of the size of yeast mtDNA, using electron microscopy and renaturation kinetics. 4. A comparison of the fragmentation pattern of mtDNAs from S. carlsbergensis and various strains of Saccharomyces cerevisiae with endonuclease HindII + III suggests that the overall gene order is similar.
Mol Gen Genet 1975 Dec 30
PMID:The organization of genes in yeast mitochondrial DNA II. The physical map of EcoRI and HindII + III fragments. 76 43

We estimate that E. coli RNA polymerase is able to form stable, rifampicin-resistant, pre-intiation complexes with Adenovirus 2 DNA at three to six binding sites. The number of RNA chains initiated from such complexes has been determined form the incorporation of gamma-32P-ATP and -GTP at two rifampicin concentrations (7 mug/ml and 24 mug/ml) and after pre-incubation at either 25 or 37 degrees C. The total number of RNA chains initiated ranges from 2.6 per Ad 2 DNA molecule at a rifampicin concentration of 24 mug/ml and pre-incubation temperature of 25 degrees C, to 5.4 per Ad 2 DNA molecule at a rifampicin concentration of 7 mug/ml and pre-incubation temperature of 37 degrees C. Efficient initiation with GTP occurs only after pre-incubation at 37 degrees C whereas initiation with ATP is equally as efficient at either pre-incubation temperature. Promoters for initiation with ATP have been localized to the leftmost 58% of the Ad 2 DNA molecule, defined by the EcoR.RI restriction endonuclease fragment A; promoters for initiation with GTP are located on the remaining 42% of the Ad2 DNA molecule. It is likely that on Adenovirus 2 DNA each RNA chain is initiated from a unique binding site which constitutes a seperate promoter for E. coli RNA polymerase.
Mol Gen Genet 1976 Jan 16
PMID:In vitro transcription of adenovirus 2 DNA. II. Quantification and localization of promoters for E. coli RNA polymerase. 76 52

Kinetics was studied of DNA degradation, processing and synthesis in the course of post-radiation incubation (irradiation dose 0-2000 erg/mm2). It has been shown that contrary to the endonuclease splitting of DNA strands, DNA degradation requires energy. DNA degradation is not enhanced upon an increase of the irradiation up to 400 erg/mm2 and more and at the incubation duration exceeding 120 min. The degradation involves not more than 40% of the total DNA quantity. It takes place in the absence of resynthesis registered by the incorporation of [3h] thymidine and 32P and dephinylamine reaction. The number of single-strand breaks in DNA (per one E. coli chromosome strans) reaches a maximum value after 120-180 min. of incubation. This maximal value is linearily increased upon an increase of the irradiation dose from 0 to 1200 erg/mm2 and does not change when the dose increases further. The number of single-strand breaks does not exceed 35-50, this value being dependent on the presence of glucose. On the basis of the data obtained a suggestion is put forward that in the course of the reparative degradation of DNA, prolonged (10(4)-10(5) nucleotides) single-stranded regions are formed. Possible role of these 'nicks" in the appearance of mutations is discussed.
Mol Biol (Mosk)
PMID:[Structure of the DNA molecule in the course of reparation process after ultraviolet irradiation of E. coli cells]. 76 45

The gal3 mutation of E. coli is an insertion of a DNA sequence, 1,100 base pairs in length, into the operator-promoter region of the galactose operon. This mutation reverts spontaneously to gal+ by excision of the insertion to produce stable, inducible revertants, or by tandem duplications of the gal operon to produce unstable, constitutive revertants. The nature of a third class of revertants, which are stable and constitutive, is the subject of the present study. The stable, constitutive class of revertants included approximately 30% of all gal+ revertants obtained from a gal3 (lambda) strain. Although the constitutive reversions could be transduced by lambda, the efficiency was found to be extremely poor and the rare transductants which did appear seemed to originate from abnormal transducing particles. It was concluded that these reversions were not normally packaged by lambda. In order to facilitate the packaging of these reversions, the chlD-pgl region was deleted from the parent gal3 (lambda) strain. Unexpectedly, the gal3 mutation in the majority of these deletions reverted to produce stable, constitutive reversions exclusively. The explanation proposed was that the chlL-pgl deletions had also removed part of the gal operator-promoter. These revertants were not considered to be true representatives of the stable, constitutive class. The specificity of deletion end-points at the insertion was found only in the gal3 (lambda) strain, and not in gal+, gal+(lambda), or gal3 strains. Moreover, the frequency of spontaneous chlD-pgl deletions increased 10- to 15-fold in presence of the gal3 insertions. A lambdagal phage bearing a true stable, constitutive reversion (galc200) was isolated from the revertant strain by subsequent deletion of the chlD-pgl segment (delta31). Electron micrographs of lambdagal+ and lambdac200 delta31(chlD pgl) DNA heteroduplexes were interpreted to indicate that the stable, constitutive reversion had arisen by a deletion of 3/4 of the gal3 insertion sequence. The main conclusions are: (i) the stable, constitutive reversions of gal3 can arise by partial deletions of the insertion sequence, apparently by elimination of the nucleotide sequence which causes polarity; (ii) the chlD-pgl deletions may exhibit preferential termination at the right extremity of the gal3 insertion in presence of prophage lambda; and (iii) the gal3 insertion appears to inhibit the production of lambdagal particles by providing a nucleotide sequence which is recognized and degraded by a specific endonuclease. It is suggested that inhibition of transducing particle formation by gal3 and the preferred termination of deletions at gal3 might represent related phenomena.
Mol Gen Genet 1976 Dec 31
PMID:Reversion of the gal3 mutation of Escherichia coli: partial deletion of the insertion sequence. 77 85

A general method has been developed for the deletion of restriction endonuclease sites in bacterial plasmid DNA. The procedure involves partial digestion of the covalently closed circular plasmid DNA with an appropriate restriction endonuclease under conditions which allow accumulation of unit-length linear DNA molecules, a controlled digestion of the exposed 5' ends with the lambda 5'-exonuclease, and in vivo recircularization of the resulting linear DNA in a bacterial host cell. The method has been used for the deletion of one of the two EcoRI sites in the plasmid pML2 (colE1-Km). Two of the resulting plasmids, pCR1 and pCR11, have a single EcoRI cleavage site, but retain genetic determinants specifying resistance to colicin E1 and kanamycin, and thus may be useful as vectors for the cloning and amplification of DNA in bacteria.
Mol Gen Genet 1976 May 07
PMID:A method for the deletion of restriction sites in bacterial plasmid deoxyribonucleic acid. 77 81

The action of Escherichia coli restriction endonuclease R1 (EcoR1) on DNA isolated from Saccharomyces cerevisiae (strain MAR-33) generates three predominent homogenously sized DNA fragments (species of 1.8, 2.2 and 2.5 kilo nucleotide base pairs (KB). Many DNA species of molecular weight greater than 2 million daltons can be recognized upon incomplete EcoR1 digestion of yeast DNA. Four additional DNA species ranging from 0.3--0.9 KB can be identified as the second major class of EcoR1-yeast DNA products. Hybridization with radioactive ribosomal RNA (rRNA) and competition with nonradioactive rRNA show that of the three predominent EcoR1-yeast DNA species, the 2.5 KB species hybridizes only with the 25S rRNA while the lighter 1.8 KB species hybridizes with the 18S rRNA. The intermediate DNA species of 2.2 KB hybridizes to a small extent with the 25S rRNA and could be a result of the presence of the 2.5 KB DNA species. The mass proportions and hybridization values of these 3 DNA species account for about 60% of the total ribosomal DNA (rDNA). The 5 Eco-R1-yeast DNA species of less than 0.9 KB (4 major and 1 minor species) hybridize to varying degrees with the 2 rRNA and can be grouped in two classes. In one class there are 3 DNA species that hybridize exclusively with the 18S rRNA. In the second class there are 2 DNA species that besides hybridizing predominently with the 25S rRNA also hybridize with the 18S rRNA. The 7 EcoR1-yeast DNA species (excluding the 2.2 KB DNA species) that hybridize with the two rRNA account for nearly a 5 million dalton DNA segment, which is very close to the anticipated gene size of rRNA precursor molecule. If the 2.2 KB DNA species is a part of the rDNA that is not transcribed or 5 sRNA then the cistron encoding the rRNA in S. cerevisiae has at least 8 EcoR1 recognition sites resulting in 8 DNA fragments upon digestion with the EcoR1. Consideration is given to the relationship of the rRNA species generated by EcoR1 digestion and the chromosomes containing ribosomal cistrons.
Mol Gen Genet 1976 Aug 19
PMID:Characterization of yeast ribosomal DNA fragments generated by EcoR1 restriction endonuclease. 78 55

Lambda-transducing phages carrying segments of the Escherichia coli chromosome in the aroE-trkA region have been isolated and shown by hybridization to carry an rRNA gene (rrnD). The most likely gene order is trkA aroE rrnD. The EcoRI and SmaI endonuclease cutting pattern of the rrnD gene is identical with the one of rrnB, differented from rrnC.
Mol Gen Genet 1976 Aug 02
PMID:A ribosomal RNA gene of Escherichia coli (rrnD) on lamnda daro E specialized transducing phages. 79 95


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>