Project description:PU.1 is an Ets family transcription factor that is essential for the differentiation of both myeloid and lymphoid cells. PU.1 is down-regulated in classical Hodgkin lymphoma cells via methylation of the PU.1 promoter. To evaluate whether down-regulation of PU.1 is essential for the growth of cHL cells, we generated KM-H2 derived cell lines conditionally express PU.1 by tet-off system (designated KM-H2tetPU.1). Conditonally expressed PU.1 by tetracycline removal induced complete growth arrest and apoptosis in KM-H2 cells. To elucidate the mechanisms underlying cell cycle arrest and apoptosis induced by PU.1, we compared gene expression profiles of KM-H2tetPU.1 cells 0, 1 and 3 days after PU.1 induction, by DNA microarray.
Project description:PU.1 is an Ets family transcription factor that is essential for the differentiation of both myeloid and lymphoid cells. PU.1 is down-regulated in classical Hodgkin lymphoma cells via methylation of the PU.1 promoter. To evaluate whether down-regulation of PU.1 is essential for the growth of cHL cells, we generated KM-H2 derived cell lines conditionally express PU.1 by tet-off system (designated KM-H2tetPU.1). Conditonally expressed PU.1 by tetracycline removal induced complete growth arrest and apoptosis in KM-H2 cells. To elucidate the mechanisms underlying cell cycle arrest and apoptosis induced by PU.1, we compared gene expression profiles of KM-H2tetPU.1 cells 0, 1 and 3 days after PU.1 induction, by DNA microarray. We extracted total RNA from KM-H2tetPU.1 cells 0, 1 and 3 days after PU.1 induction by tetracycline removal. We compared gene expression profiles of KM-H2tetPU.1 cells 0, 1 and 3 days after PU.1 induction using DNA microarray analysis. 4 independent experiments were performed with each RNA samples.
Project description:Rhodamin 123 is a dye which can be used to detect the activity of ABC transporters. We observed that after staining of KM-H2 Hodgkin lymphoma cells with Rhodamin 123, part of the cells rapidly eliminated the dye, while another part of the cells retained the dye for a longer time. We compared the transcriptome of KM-H2 Hodgkin lymphoma cells with high Rhodamin 123 efflux capacity and KM-H2 cells with low Rhodamin 123 efflux capacity.
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: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.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in 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.