Project description:Whole genome microarrays were probed with total mRNA from PTD-DRBD GAPDH siRNA treated H1299 cells at 12 h and 24 h. Using a 1.6x fold increase/decrease filter of cellular mRNAs, we detected a dramatic reduction in the target GAPDH mRNA along with a limited number of both up and down regulated genes. The up regulated genes were reduced in numbers and to nearly background 1.6x levels at 24 h, while the down regulated genes increased slightly in numbers and maintained a similar magnitude at 24 h. In contrast, lipofection treated cells showed both a dramatic increase in both the total number of genes altered and the magnitude of the increase. In addition, the numbers of genes affected increased between 12 h and 24 h, suggesting that lipofection of siRNAs into cells results in a substantial alteration to the transcriptome and may thereby confound interpretation of experimental outcomes. Moreover, the GAPDH specific knockdown was significantly smaller than PTD-DRBD mediated knockdown. Total RNA obtained from H1299 cells treated with PTD-DRBD GAPDH siRNA, Lipofection GAPDH siRNA or PBS (Control) after 12 or 24 hours post-treatment
Project description:Whole genome microarrays were probed with total mRNA from PTD-DRBD GAPDH siRNA treated H1299 cells at 12 h and 24 h. Using a 1.6x fold increase/decrease filter of cellular mRNAs, we detected a dramatic reduction in the target GAPDH mRNA along with a limited number of both up and down regulated genes. The up regulated genes were reduced in numbers and to nearly background 1.6x levels at 24 h, while the down regulated genes increased slightly in numbers and maintained a similar magnitude at 24 h. In contrast, lipofection treated cells showed both a dramatic increase in both the total number of genes altered and the magnitude of the increase. In addition, the numbers of genes affected increased between 12 h and 24 h, suggesting that lipofection of siRNAs into cells results in a substantial alteration to the transcriptome and may thereby confound interpretation of experimental outcomes. Moreover, the GAPDH specific knockdown was significantly smaller than PTD-DRBD mediated knockdown.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
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.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.