Project description:This SuperSeries is composed of the following subset Series: GSE35112: Genome-wide analysis of gene expression and nuclear/cytoplasmic distribution by compound 1 treatment [293T-M] GSE35113: Genome-wide analysis of gene expression and nuclear/cytoplasmic distribution by compound 1 treatment [293T_NS1-1] GSE35114: Genome-wide analysis of gene expression and nuclear/cytoplasmic distribution by compound 1 treatment [293T_NS1-2] GSE35115: Genome-wide analysis of gene expression by compound 1 treatment [HBEC_3h] GSE35116: Genome-wide analysis of gene expression by compound 1 treatment [HBEC_6_12hr] Refer to individual Series
Project description:Analysis of cellular response to DHODH inhibition at gene expression and nuclear/cytoplasmic distribution level. The NS1 protein of influenza virus is a major virulence factor essential for virus replication as it re-directs the host cell to promote viral protein expression. NS1 inhibits cellular mRNA processing and export, down-regulating host gene expression and enhancing viral gene expression. We report here the identification of a non-toxic quinoline carboxylic acid that reverts the inhibition of mRNA nuclear export by NS1, in the absence or presence of virus. This quinoline carboxylic acid directly inhibited dihydroorotate dehydrogenase (DHODH), a host enzyme required for *de novo* pyrimidine biosynthesis, and partially reduced pyrimidine levels. This effect induced NXF1 expression, which promoted mRNA nuclear export in the presence of NS1. The release of NS1-mediated mRNA export block by DHODH inhibition also occurred in the presence of VSV M protein, another viral inhibitor of mRNA export. This reversal of mRNA export block allowed expression of antiviral factors. Thus, pyrimidines play a necessary role in the inhibition of mRNA nuclear export by virulence factors. Five million 293T cells were non-transfected or transfected with 6ug of pEGFPN3-M-GFP for 16h. Then, cells were untreated or treated with compound 1(5uM) for 24h. RNA from total cell extracts or from nuclear or cytoplasmic fractions were obtained
Project description:Analysis of cellular response to DHODH inhibition at gene expression and nuclear/cytoplasmic distribution level. The NS1 protein of influenza virus is a major virulence factor essential for virus replication as it re-directs the host cell to promote viral protein expression. NS1 inhibits cellular mRNA processing and export, down-regulating host gene expression and enhancing viral gene expression. We report here the identification of a non-toxic quinoline carboxylic acid that reverts the inhibition of mRNA nuclear export by NS1, in the absence or presence of virus. This quinoline carboxylic acid directly inhibited dihydroorotate dehydrogenase (DHODH), a host enzyme required for *de novo* pyrimidine biosynthesis, and partially reduced pyrimidine levels. This effect induced NXF1 expression, which promoted mRNA nuclear export in the presence of NS1. The release of NS1-mediated mRNA export block by DHODH inhibition also occurred in the presence of VSV M protein, another viral inhibitor of mRNA export. This reversal of mRNA export block allowed expression of antiviral factors. Thus, pyrimidines play a necessary role in the inhibition of mRNA nuclear export by virulence factors. Five million 293T cells were non-transfected or transfected with 6ug of pCAGGS-NS1 for 16h. Then, cells were untreated or treated with compound 1(5uM) for 24h. RNA from total cell extracts or from nuclear or cytoplasmic fractions were obtained
Project description:Analysis of cellular response to DHODH inhibition at gene expression and nuclear/cytoplasmic distribution level. The NS1 protein of influenza virus is a major virulence factor essential for virus replication as it re-directs the host cell to promote viral protein expression. NS1 inhibits cellular mRNA processing and export, down-regulating host gene expression and enhancing viral gene expression. We report here the identification of a non-toxic quinoline carboxylic acid that reverts the inhibition of mRNA nuclear export by NS1, in the absence or presence of virus. This quinoline carboxylic acid directly inhibited dihydroorotate dehydrogenase (DHODH), a host enzyme required for *de novo* pyrimidine biosynthesis, and partially reduced pyrimidine levels. This effect induced NXF1 expression, which promoted mRNA nuclear export in the presence of NS1. The release of NS1-mediated mRNA export block by DHODH inhibition also occurred in the presence of VSV M protein, another viral inhibitor of mRNA export. This reversal of mRNA export block allowed expression of antiviral factors. Thus, pyrimidines play a necessary role in the inhibition of mRNA nuclear export by virulence factors. Five million 293T cells were non-transfected or transfected with 6ug of pCAGGS-NS1 for 16h. Then, cells were untreated or treated with compound 1(5uM) for 24h. RNA from total cell extracts or from nuclear or cytoplasmic fractions were obtained
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.