Project description:We identified two isoforms of human MKL1 that differ in their N-terminal domains. Since MKL1 is a transcriptional coactivator of SRF and regulates many SRF target genes, we wanted to analyze if transcription is differentially regulated by the two isoforms upon stimulation of the Rho-actin-MKL1-SRF pathway.
Project description:We identified two isoforms of human MKL1 that differ in their N-terminal domains. Since MKL1 is a transcriptional coactivator of SRF and regulates many SRF target genes, we wanted to analyze if transcription is differentially regulated by the two isoforms upon stimulation of the Rho-actin-MKL1-SRF pathway. Activity of the Rho-actin-MKL1 pathway was induced in EcR293 cell lines stably over-expressing the empty vector control, a 5’UTR-full length MKL1_S construct, or a 5’UTR-full length MKL1_L construct by LPA treatment.
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: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. Two-condition experiment, Normoxic MSCs vs. Hypoxic MSCs.
Project description:Megakaryoblastic Leukemia 1 (MKL1) was identified as part of the t(1;22) translocation specific to acute megakaryoblastic leukemia, but nothing is known regarding its role in hematopoiesis. Here we show that overexpression of MKL1 enhances megakaryocytic differentiation of the Human Erythroleukemia cell line (HEL). Microarray analysis reveals that MKL1 promotes expression of megakaryocyte-specific genes such as glycoprotein V (GP5), as well as cytoskeletal and adhesion molecule genes relevant to megakaryocyte differentiation and proplatelet formation. MKL1 is a transcriptional coactivator of Serum Response Factor. In this study, MKL1 also upregulates known SRF targets. Results provide insight into the role of MKL1 in megakaryocytopoiesis.
Project description:Cellular differentiation is regulated through activation and repression of defined transcription factors. A hallmark of differentiation is a pronounced change in cell shape, which is determined by dynamics of the actin cytoskeleton. In de-differentiated fat (DFAT) cells and 3T3-L1 cells, we showed that treatment with the ROCK inhibitor Y-27632, by inducing remodeling of the actin cytoskelton, causes adipocyte differentiation. In addition, we found that depletion of MKL1, an actin binding transcriptional coactivator, elicits adipogenesis. To investigate whether regulation of MKL1 by actin cytoskeleton dynamics drives adipocyte differentiation, we compared the gene expression changes resulting from DFAT cells after treatment with Y-27632 and transfection of Mkl1 siRNA. Using Affymetrix mouse genome array, we compared global gene expression profiles in DFAT cells after treatment with Y-27632 and transfection with Mkl1 siRNA to search for particular biological functions in genes of which expression intensities were increased and decreased.
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:Cellular differentiation is regulated through activation and repression of defined transcription factors. A hallmark of differentiation is a pronounced change in cell shape, which is determined by dynamics of the actin cytoskeleton. In de-differentiated fat (DFAT) cells and 3T3-L1 cells, we showed that treatment with the ROCK inhibitor Y-27632, by inducing remodeling of the actin cytoskelton, causes adipocyte differentiation. In addition, we found that depletion of MKL1, an actin binding transcriptional coactivator, elicits adipogenesis. To investigate whether regulation of MKL1 by actin cytoskeleton dynamics drives adipocyte differentiation, we compared the gene expression changes resulting from DFAT cells after treatment with Y-27632 and transfection of Mkl1 siRNA.
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.