Search results for "OxyR"
showing 10 items of 216 documents
Production of biologically active light chain of tetanus toxin inEscherichia coli
1993
AbstractThe activity of the light (L) chain of tetanus toxin, and of mutants constructed by site-directed mutagenesis, was studied by expression and purification of the proteins from E. coli. Wild-type recombinant L chain (pTet87) was active in the inhibition of exocytosis from cultured bovine adrenal chromaffin cells, although at a level 5–15% of that of L chain purified from tetanus toxin. L chain mutants which terminated at Leu-438 (pTet89), or which contained a Cys-to-Ser mutation at residue 439 (pTet88) were equally as active as the full-length recombinant protein. The reduced activity of pTet87 L chain correlated with C-terminal proteolysis of the protein upon purification. A tryptic …
Cloning of a novel putative G-protein-coupled receptor (NLR) which is expressed in neuronal and lymphatic tissue.
1993
AbstractA novel G-protein-coupled receptor was isolated from mouse and rat neuronal and lymphatic tissues. The amino acid sequence of the rat receptor (rNLR) shows an overall homology of 80% to a recently cloned receptor from Burkitt's lymphoma cells (BLR1) which is exclusively expressed in lymphatic tissues [(1992) Eur. J. Immunol. 22, 2795]. Much less homology between rNLR and BLR1 was observed at the N-terminus (about 40%), whereas rNLR and the mouse homologue mNLR show 92% amino acid identity. Northern blot analysis of NLR revealed a predominant 5.5 kb mRNA species in various brain regions and neuronal cell lines, whereas in the spleen a 3 kb transcript is predominant. This distribution…
More accuracy to the EROD measurements—The resorufin fluorescence differs between species and individuals
2012
Ethoxyresorufin-O-deethylase (EROD) activity is a biomarker of exposure to planar aromatic hydrocarbons, and it is often measured from the S9 fraction. The effect of the liver S9 fraction of seven boreal freshwater fish species on the fluorescence of resorufin was studied. The S9 fractions diminished resorufin fluorescence by 40–80%, and there were large differences between species. Thus, using a resorufin standard curve without the S9 fraction leads to a large underestimation of the EROD activity. Therefore a microwell plate EROD method was developed that takes into account the effect of each sample on resorufin fluorescence. At least two mechanisms were involved in the decrease of the flu…
Expression of yeast but not human apurinic/apyrimidinic endonuclease renders Chinese hamster cells more resistant to DNA damaging agents.
1997
Abasic sites represent ubiquitous DNA lesions that arise spontaneously or are induced by DNA-damaging agents. They block DNA replication and are considered to be cytotoxic and mutagenic. The key enzymes involved in the repair of abasic sites are apurinic/apyrimidinic (AP) endonucleases which process these lesions in an error-free mechanism. To analyze the role of AP endonuclease in the protection of mammalian cells against DNA damaging agents, we have transfected both the human (APE) and the yeast (APN1) AP endonuclease in Chinese hamster cells and compared the effects of expression of these genes in stable transfectants as to survival of cells and formation of chromosomal aberrations. Alth…
HAT1 and HAT2 Proteins Are Components of a Yeast Nuclear Histone Acetyltransferase Enzyme Specific for Free Histone H4
1998
We have analyzed the histone acetyltransferase enzymes obtained from a series of yeast hat1, hat2, and gcn5 single mutants and hat1,hat2 and hat1,gcn5 double mutants. Extracts prepared from both hat1 and hat2 mutant strains specifically lack the following two histone acetyltransferase activities: the well known cytoplasmic type B enzyme and a free histone H4-specific histone acetyltransferase located in the nucleus. The catalytic subunits of both cytoplasmic and nuclear enzymes have identical molecular masses (42 kDa), the same as that of HAT1. However, the cytoplasmic complex has a molecular mass (150 kDa) greater than that of the nuclear complex (110 kDa). The possible functions of HAT1 a…
A natural A/T-rich sequence from the yeast FBP1 gene exists as a cruciform in Escherichia coli cells.
1993
Abstract Palindromic or semipalindromic sequences can adopt cruciform structures in DNA in vitro. It has been demonstrated in some cases that A/T-rich cruciforms exist also in vivo in Escherichia coli. The biological function of those structures is not understood although putative cruciforms have been found in interesting locations on replication origins, operators, or transcriptional termination regions. Here we show by means of the use of structure-dependent nucleases that the 3′ end of the yeast FBP1 gene contains a stable cruciform both in vitro and in E. coli cells and that in both cases, its extrusion depends on the DNA supercoiling state.
Centromeric heterochromatin and satellite DNA in the Chironomus plumosus species group
1994
Species of the Chironomus plumosus group display significant differences in their amount of centromeric heterochromatin. A tandem-repetitive satellite-like DNA has been isolated from C. plumosus. This DNA accounts for a major part of the centromeric heterochromatin. The DNA element has a Sau3AI restriction site ("Sau elements") and a monomer length of 165 or 166 bp. It is A-T rich (73%) and reveals a moderate DNA curvature, as shown by gel migration and computer analysis. The chromosomal localization and genomic organization of Sau elements were studied in 24 Chironomus species by in situ hybridization and (or) Southern analysis. The DNA is predominantly located in the centromeric regions …
Compromised nuclear envelope integrity drives TREX1-dependent DNA damage and tumor cell invasion
2021
Although mutations leading to a compromised nuclear envelope cause diseases such as muscular dystrophies or accelerated aging, the consequences of mechanically induced nuclear envelope ruptures are less known. Here, we show that nuclear envelope ruptures induce DNA damage that promotes senescence in non-transformed cells and induces an invasive phenotype in human breast cancer cells. We find that the endoplasmic reticulum (ER)-associated exonuclease TREX1 translocates into the nucleus after nuclear envelope rupture and is required to induce DNA damage. Inside the mammary duct, cellular crowding leads to nuclear envelope ruptures that generate TREX1-dependent DNA damage, thereby driving the …
Isolation of Vibrio vulnificus Serovar E from Aquatic Habitats in Taiwan
1999
ABSTRACT The existence of strains of Vibrio vulnificus serovar E that are avirulent for eels is reported in this work. These isolates were recovered from water and oysters and differed from eel virulent strains in (i) fermentation and utilization of mannitol, (ii) ribotyping after Hin dIII digestion, and (iii) susceptibility to eel serum. Lipopolysaccharide of these strains lacked the highest molecular weight immunoreactive bands, which are probably involved in serum resistance.
CCDC 251467: Experimental Crystal Structure Determination
2004
Related Article: J.R.Hanson, P.B.Hitchcock, I.Pibiri, F.Piozzi|2003|J.Chem.Res.||147|doi:10.3184/030823403103173291