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:SRF is a ubiquitous transcription factor that binds DNA in association with myocardin-family proteins (e.g. MKL1), or the ternary complex factor (TCF) family of ETS proteins. In primary hematopoietic cells, knockout of either SRF or MKL1 decreases megakaryocyte maturation caused thrombocytopenia, and MKL1 over-expression (MKL1OE) in the Human Erythroleukemia (HEL) cell line enhances megakaryopoiesis, but the mechanisms underlying these effects are unknown. To elucidate the role of SRF and MKL1 in megakaryopoiesis, integrated analysis was performed of anti-SRF ChIP-seq and RNA-seq data in undifferentiated and differentiated HEL cells, both with and without induction of MKL1OE. MKL1OE enhances TPA-induced megakaryopoiesis with 25% of genes upregulated, as opposed to 11% with TPA alone. MKL1OE increases SRF binding to genomic sites, and enhances expression of specific target cytoskeletal genes in response to TPA. Genes upregulated in response to TPA are predicted to be regulated by SRF and ETS factors, whereas those upregulated in TPA plus MKL1OE lack ETS binding motifs. Using ChIP-PCR, we validated that both SRF and MKL1 have increased binding at target upregulated genes, e.g. CORO1A, with MKL1OE. We show for the first time that MKL1 increases both the genomic association and activity of SRF, and upregulates genes that enhance megakaryopoiesis.
Project description:SRF is a ubiquitous transcription factor that binds DNA in association with myocardin-family proteins (e.g. MKL1), or the ternary complex factor (TCF) family of ETS proteins. In primary hematopoietic cells, knockout of either SRF or MKL1 decreases megakaryocyte maturation caused thrombocytopenia, and MKL1 over-expression (MKL1OE) in the Human Erythroleukemia (HEL) cell line enhances megakaryopoiesis, but the mechanisms underlying these effects are unknown. To elucidate the role of SRF and MKL1 in megakaryopoiesis, integrated analysis was performed of anti-SRF ChIP-seq and RNA-seq data in undifferentiated and differentiated HEL cells, both with and without induction of MKL1OE. MKL1OE enhances TPA-induced megakaryopoiesis with 25% of genes upregulated, as opposed to 11% with TPA alone. MKL1OE increases SRF binding to genomic sites, and enhances expression of specific target cytoskeletal genes in response to TPA. Genes upregulated in response to TPA are predicted to be regulated by SRF and ETS factors, whereas those upregulated in TPA plus MKL1OE lack ETS binding motifs. Using ChIP-PCR, we validated that both SRF and MKL1 have increased binding at target upregulated genes, e.g. CORO1A, with MKL1OE. We show for the first time that MKL1 increases both the genomic association and activity of SRF, and upregulates genes that enhance megakaryopoiesis.
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.