Detailed information about stage-specific changes in gene expression is crucial for understanding the gene regulatory networks underlying development and the various signal transduction pathways contributing to morphogenesis. Here, we describe the global gene expression dynamics during early murine limb development, when cartilage, tendons, muscle, joints, vasculature, and nerves are specified and the musculoskeletal system of the limbs is established. We used whole-genome microarrays to identify genes with differential expression at 5 stages of limb development (E9.5 to 13.5), during fore-limb and hind-limb patterning. We found that the onset of limb formation is characterized by an up-regulation of transcription factors, which is followed by a massive activation of genes during E10.5 and E11.5 which tampers off at later time points. Among 3520 genes identified as significantly up-regulated in the limb, we find ~30% to be novel, dramatically expanding the repertoire of candidate genes likely to function in the limb. Hierarchical and stage-specific clustering identified expression profiles that correlate with functional programs during limb development and are likely to provide new insights into specific tissue patterning processes. Here we provide for the first time, a comprehensve analysis of developmentally regulated genes during murine limb development, and provide some novel insights into the expression dynamics governing limb morphogenesis.
Global gene expression analysis of murine limb development.
Specimen part
View SamplesHMGN (high mobility group N) is a family of intrinsically disordered nuclear proteins that binds to nucleosomes, alters the structure of chromatin and affects transcription. A major unresolved question is the extent of functional specificity, or redundancy, between the various members of the HMGN protein family.
Effects of HMGN variants on the cellular transcription profile.
Specimen part
View SamplesYB-1 controls epithelial-mesenchymal transitions by restricting translation of growth-related mRNAs and enabling expression of EMT-inducing transcription factors. We used microarrays to characterize the direct transcriptional and indirect translational regulation of mRNAs by exogenous YB-1 in breast cancer cell lines.
Translational activation of snail1 and other developmentally regulated transcription factors by YB-1 promotes an epithelial-mesenchymal transition.
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View SamplesDown syndrome (DS) is the most frequent cause of human congenital mental retardation. Cognitive deficits in DS result from perturbations of normal cellular processes both during development and in adult tissues, but the mechanisms underlying DS etiology remain poorly understood. To assess the ability of iPSCs to model DS phenotypes, as a prototypical complex human disease, we generated bona-fide DS and wild-type (WT) non-viral iPSCs by episomal reprogramming. DS iPSCs selectively overexpressed chromosome 21 genes, consistent with gene dosage, which was associated with deregulation of thousands of genes throughout the genome. DS and WT iPSCs were neurally converted at >95% efficiency, and had remarkably similar lineage potency, differentiation kinetics, proliferation and axon extension at early time points. However, at later time points DS cultures showed a two-fold bias towards glial lineages.
Integration-free induced pluripotent stem cells model genetic and neural developmental features of down syndrome etiology.
Sex, Specimen part, Disease, Disease stage, Cell line
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