Project description:Our lab identified Sox9 as a specific marker and maintenance factor of mouse pancreatic progenitors (Seymour et al., PNAS, 2007). Here was wanted to identify direct targets of Sox9 in pancreatic progenitors. However, due to the limited number of pancreatic progenitors in the developing mouse, we used in vitro derived pancreatic progenitors to determine direct targets of Sox9. We performed ChIP-seq analysis for Sox9 and determined its direct targets in the human genome. Using pancreatic progenitors that were derived from human embryonic stem cells, we were able to successfully find targets that were pancreas specific as well as those targets that are important in other endodermal lineages.
Project description:Transcriptome profiling of hESC-derived endoderm progenitors by RNA-seq. RNA-seq analysis during the stepwise progression of hESC toward the pancreatic progenitors, at five defined stages of differentiation and expansion: hESC, ADE, VFG.p3, VFG.p6. PE.
Project description:To assess the effects of quantitative SOX9 dosage changes on chromatin accessibility in hESC-derived cranial neural crest cells, we performed genome editing of the H9 hESC lines to tag SOX9 with FKBPV36, V5, and mNeonGreen. Upon differentiating edited hESC to cranial neural crest cells using an established protocol, addition of differing concentrations of the degrader molecule dTAGV-1 results in different SOX9 concentrations, as measured by flow cytometry. We then profiled chromatin accessibility in each of these SOX9 concentrations
Project description:Genes specific to Sox9+ pancreatic progenitors were identified by comparing the gene expression in embryonic and adult Sox9+ cells. We used microarray analysis to detail the global changes in gene expression as Sox9 positive embryonic pancreatic progenitors differentiatiate into adult ductal cells or the endocrine lineage.
Project description:The genomic regulatory programs that underlie human organogenesis are poorly understood. Human pancreas development, in particular, has pivotal implications for pancreatic regeneration, cancer, and diabetes. We have now created maps of transcripts, active enhancers, and transcription factor networks in pancreatic multipotent progenitors obtained from human embryos, or derived in vitro from human embryonic stem cells. This revealed that artificial progenitors recapitulate salient transcriptional and epigenomic features of their natural counterparts. Using this resource, we show that TEAD1, a transcription factor controlled by Hippo signaling, is a core component of the combinatorial code of pancreatic progenitor enhancers. TEAD thus activates genes encoding regulators of signaling pathways and stage-specific transcription factors that are essential for normal pancreas development. Accordingly, chemical and genetic perturbations of TEAD and its coactivator YAP inhibited expression of known regulators such as FGFR2 and SOX9, and suppressed the proliferation and expansion of mouse and zebrafish pancreatic progenitors. These findings provide a resource of active enhancers and transcripts in human pancreatic multipotent progenitors, and uncover a central role of TEAD and YAP as signal-responsive regulators of the transcriptional program of early pancreas development.
Project description:To assess the effects of SOX9 depletion on active chromatin marks in hESC-derived cranial neural crest cells, we performed genome editing of the H9 hESC lines to tag SOX9 with FKBPV36, V5, and mNeonGreen. Upon differentiating edited hESC to cranial neural crest cells using an established protocol, addition of the degrader molecule dTAGV-1 results in SOX9 depletion. We then profiled the active chromatin mark H3K27ac by ChIP-Seq in undepleted CNCCs or CNCCs in which SOX9 was depleted for 3h or 24h. We also titrated SOX9 to four distinct levels with dTAGV-1 and assessed SOX9 binding by V5 ChIP-seq, as well as TWIST1 and TFAP2A binding by ChIP-seq.
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:To assess the effects of SOX9 depletion on transcription in hESC-derived cranial neural crest cells, we performed genome editing of the H9 hESC lines to tag SOX9 with FKBPV36, V5, and mNeonGreen. Upon differentiating edited hESC to cranial neural crest cells using an established protocol, addition of the degrader molecule dTAGV-1 results in SOX9 depletion. We then profiled transcription by metabolic labeling of RNA (SLAM-Seq) in undepleted CNCCs or CNCCs in which SOX9 was depleted for 3h or 24h
Project description:To assess the effects of quantitative SOX9 dosage changes on gene expression in hESC-derived cranial neural crest cells, we performed genome editing of the H9 hESC lines to tag SOX9 with FKBPV36, V5, and mNeonGreen. Upon differentiating edited hESC to cranial neural crest cells using an established protocol, addition of differing concentrations of the degrader molecule dTAGV-1 results in different SOX9 concentrations, as measured by flow cytometry. We then profiled gene expression profiling in each of these SOX9 concentrations