Project description:With this study we aimed to characterize the changes invoked in glial progenitor cells by activation of the endogenous copy of the master transcription factor Sox1. For this study, a progenitor cell line was derived from ES cells carrying a heterozygous GFP knock-in in the Sox1 ORF. Sox1 positive cells were identified by GFP expression, and separated by FACS. As control population, Sox1 negative progenitors were used, as well as GFP sorted and unsorted, Sox1 positive Neuroepithelial cells derived from the same ES cell line.
Project description:To understand how SOX1's binding profile in neural progenitor with different regional identities, we differentiated hESC into neural progenitors with rostral and caudal identies throught modulating Wnt signaling pathway. We collected cells at neural differentiation day 4 and 8, and performed SOX1 ChIP-seq to investigate SOX1's genome wide binding profiles. These results provide important information for the mechanism underlying SOX1's functions in early regionalization.
Project description:It remains controversial whether the routes from differentiated cells to iPSCs are related to the reverse order of normal developmental processes or independent of them. Here, we generated iPSCs from mouse astrocytes by three (Oct3/4, Klf4 and Sox2 (OKS)), two (OK), or four (OKS plus c-Myc) factors. Sox1, a neural stem cell (NSC)-specific transcription factor, is transiently upregulated during reprogramming and Sox1-positive cells become iPSCs. The upregulation of Sox1 is essential for OK-induced reprogramming. Genome-wide analysis revealed that the gene expression profile of Sox1-expressing intermediate-state cells resembles that of NSCs. Furthermore, the intermediate-state cells are able to generate neurospheres, which can differentiate into both neurons and glial cells. Remarkably, during MEF reprogramming, neither Sox1 upregulation nor an increase in neurogenic potential occurs. Thus, astrocytes are reprogrammed through an NSC-like state, suggesting that reprogramming partially follows the retrograde pathway of normal developmental processes. To investigate the gene expression profile of intermediate-state cells during astrocyte reprogramming, we performed genome-wide gene expression analysis in five samples; starting astrocytes, intermediate-state cells expressing Sox1-GFP, NSCs, iPSCs established from astrocytes, and iPSCs established from MEFs (iPS-MEF-Ng-20D-17) that had previously been reported (Okita, K. et al. Nature 448: 313-317 (2007)).
Project description:During human embryogenesis, primitive neural cells start to be generated at the time of gastrulation and gradually acquire regional identities, which is a process called neural patterning. But how intrinsic factors respond to exogenous patterning signals remains poorly understood. Human Embryonic Stem Cells (hESCs) provide a great model to recapitulate this process. Through exogenous manipulation of canonical WNT signaling activation during neural differentiation, dose-dependent specification of regionally defined neural progenitors ranging from the telencephalic forebrain to posterior hindbrain could be rapidly and efficiently induced. Unexpectedly, we find that SOX1, generally referred as a pan-neural gene, displays a regional specific distribution in the human neural patterning process. To investigate the expression and function of SOX1 efficiently, we have generated the SOX1-EGFP reporter and SOX1-knockout (KO) hESC lines using the CRISPR/Cas9 system. SOX1 is initially expressed across the mes–met border and peaked in the metencephalon region at the early regional specification stage. Its depletion leads to the posterior shift of the mes–met border. Therefore, SOX1 is required to define the border at a correct region. In-depth analysis of SOX1 ChIP-sequencing and transcriptome data will provide more insights into how SOX1 determines the mes-met border formation and identify the downstream targets of SOX1. This study identifies SOX1 as one of the intrinsic factors key for the prepattern establishment in the developing central nervous system, particularly for defining the isthmus position.
Project description:It remains controversial whether the routes from differentiated cells to iPSCs are related to the reverse order of normal developmental processes or independent of them. Here, we generated iPSCs from mouse astrocytes by three (Oct3/4, Klf4 and Sox2 (OKS)), two (OK), or four (OKS plus c-Myc) factors. Sox1, a neural stem cell (NSC)-specific transcription factor, is transiently upregulated during reprogramming and Sox1-positive cells become iPSCs. The upregulation of Sox1 is essential for OK-induced reprogramming. Genome-wide analysis revealed that the gene expression profile of Sox1-expressing intermediate-state cells resembles that of NSCs. Furthermore, the intermediate-state cells are able to generate neurospheres, which can differentiate into both neurons and glial cells. Remarkably, during MEF reprogramming, neither Sox1 upregulation nor an increase in neurogenic potential occurs. Thus, astrocytes are reprogrammed through an NSC-like state, suggesting that reprogramming partially follows the retrograde pathway of normal developmental processes. To investigate the gene expression profile of intermediate-state cells during astrocyte reprogramming, we performed genome-wide gene expression analysis in five samples; starting astrocytes, intermediate-state cells expressing Sox1-GFP, NSCs, iPSCs established from astrocytes, and iPSCs established from MEFs (iPS-MEF-Ng-20D-17) that had previously been reported (Okita, K. et al. Nature 448: 313-317 (2007)). Two (NSCs, iPSCs from astrocytes and MEFs) or three (astrocytes, intermediate-state cells) biological replicates were prepared for microarray samples. Total RNA was extracted with an RNeasy kit (Qiagen). cDNA synthesis and transcriptional amplification were performed using 50-100 ng of total RNA with the GeneChip WT PLUS Reagent Kit (Affymetrix). Fragmented and biotin-labeled cDNA targets were hybridized to GeneChip Mouse Gene 1.0 ST arrays (Affymetrix) according to the manufacturerâ??s protocol. Hybridized arrays were scanned using an Affymetrix GeneChip Scanner.
Project description:DNA methylation plays critical roles in gene regulation and cellular specification without altering DNA sequences. The wide application of reduced representation bisulfite sequencing (RRBS) and whole genome bisulfite sequencing (bis-seq) opens the door to study DNA methylation at single CpG site resolution. One challenging question is how best to test for significant methylation differences between groups of biological samples in order to minimize false positive findings. Current methods to analyze genome-wide bisulfite sequencing data use a smoothing approach or a simple statistical test based on the binomial distribution. Comparative DNA methylation profiling in AML blasts and normal CD34(+) control cells
Project description:We applied Illumina Human Methylation450K array to perform a genomic-scale single-site resolution DNA methylation analysis in neuronal and nonneuronal (primarily glial) nuclei separated from the orbitofrontal cortex of postmortem human brain. The findings were validated using enhanced reduced representation bisulfite sequencing. We identified thousands of sites differentially methylated (DM) between neuronal and nonneuronal cells. The DM sites were depleted within CpG islandM-bM-^@M-^Scontaining promoters but enriched in predicted enhancers. Classification of the DM sites into those undermethylated in neurons (neuronal type) and those undermethylated in nonneuronal cells (glial type), combined with findings of others that methylation within control elements typically negatively correlates with gene expression, yielded large sets of predicted neuron-specific and nonneuron-specific genes. These sets of predicted genes were in excellent agreement with the available direct measurements of gene expression in human and mouse. We also found a distinct set of DNA methylation patterns that were unique for neuronal cells. In particular, neuronal-type differential methylation was overrepresented in CpG island shores, enriched within gene bodies but not in intergenic regions, and preferentially harbored binding motifs for a distinct set of transcription factors, including neuron-specific activity-dependent factors. Finally, non-CpG methylation was substantially more prevalent in neurons than in nonneuronal cells. Extended Reduced Representation Bisulfite Sequencing (ERRBS) was performed on genomic DNA to validate the Infinium HM450K DNA methylation data (Kozlenkov et. al., 2013, Nucleic Acids Research, accepted for publication).
Project description:During retinal development, progenitor cells give rise to six different types of neurons, and one glial cell. This process requires the expression of genes that confer specific functions and identity to each cell. Previous works have reported the miRNAs expression profile in retina, but is still necessary to further define individual retinal cell populations profiles. We isolated postmitotic mice CD73-positive Rods, Müller glial cells and Retinal Progenitors Cells (E17.5); we then analyzed their miRNA profile expression by microarrays. Using wild type mice we FACS-isolated postmitotic CD73-positive Rods (posnatal day 5). We isolated primary Müller glia cultures from postnatal day 8 mice and retinal progenitors cells from E17.5 mouse embryos; we then sent the samples to the gene expression unit at Instituto de Medicina Genomica (INMEGEN), to analyze their miRNA profile expression by microarrays.
Project description:During retinal development, progenitor cells give rise to six different types of neurons, and one glial cell. This process requires the expression of genes that confer specific functions and identity to each cell. Previous works have reported the miRNAs expression profile in retina, but is still necessary to further define individual retinal cell populations profiles. We isolated postmitotic mice CD73-positive Rods, Müller glial cells and Retinal Progenitors Cells (E17.5); we then analyzed their miRNA profile expression by microarrays.