Project description:We identified p63 target genes and binding sites responsible for ectodermal defects by genome-wide profiling of p63 binding using ChIP-seq and expression analysis in human primary keratinocytes from patients with p63 mutations. As proof of principle, we identified a novel de novo microdeletion causing limb defects (SHFM1) that includes a p63 binding site functioning as a cis-regulatory element to control expression of the distally located DLX5/DLX6 genes essential for limb development. Our data demonstrate that target genes and regulatory elements detected in this study can serve as powerful tools to identify causative mutations of unresolved ectodermal disorders. ChIP-seq profiles of p63 in primary human keratinocytes established from two different normal individuals.
Project description:The transcription factor p63 is a master regulator of ectoderm development essential for epidermal specification. Although previous studies have highlighted the role of p63 triggering the epidermal transcriptomic program, its precise mechanism of target gene regulation in the complex context of a developing embryo remains poorly understood. Here, we used zebrafish embryos to analyze in vivo how p63 regulates the expression of its target genes during development. We generated tp63-knock-out mutants that recapitulate human phenotypes and show down-regulated epidermal gene expression. Following p63-binding dynamics during development, we found two distinct functions clearly separated in space and time. During early development, p63 binds enhancers associated to neural genes, where it limits Sox3 binding and reduces the expression of these neural genes. Indeed, we show that p63 and Sox3 are co-expressed in the neural plate border. Later in development, p63 binds enhancers associated to epidermal genes and promotes their expression, acting as a pioneer factor, as it binds to non-accessible chromatin and is required for its opening. Therefore, our results suggest that p63 is an important regulator of cell fate decisions during ectoderm specification, promoting the epidermal fate and inhibiting the neural program.
Project description:We identified p63 target genes and binding sites responsible for ectodermal defects by genome-wide profiling of p63 binding using ChIP-seq and expression analysis in human primary keratinocytes from patients with p63 mutations. As proof of principle, we identified a novel de novo microdeletion causing limb defects (SHFM1) that includes a p63 binding site functioning as a cis-regulatory element to control expression of the distally located DLX5/DLX6 genes essential for limb development. Our data demonstrate that target genes and regulatory elements detected in this study can serve as powerful tools to identify causative mutations of unresolved ectodermal disorders.
Project description:Tightly controlled gene expression orchestrated by the transcription factor p63 during epithelial differentiation is important for development of epithelial-related structures such as epidermis, limb and craniofacial regions. How p63 regulates spatial and temporal expression of its target genes during these developmental processes is however not yet clear. By epigenomics profiling in stem cells established from one of these epithelial structures, the epidermis, we provide a global map of p63-bound regulatory elements that are categorized as single enhancers and clustered enhancers during epidermal differentiation. Transcriptomics analysis shows dynamic gene expression patterns during epidermal differentiation that correlates with the activity of p63-bound enhancers rather than with p63 binding itself. Only a subset of p63-bound enhancers is active in epidermal stem cells, and inactive p63-bound enhancers appear to function in gene regulation during the development of other epithelial tissues. Our data suggest a paradigm that p63 bookmarks genomic loci during the commitment of the epithelial lineage and regulates gene expression in different epithelial tissues through tissue-specific active enhancers. The catalogue of differentially expressed epidermal genes including non-coding RNAs and epithelial enhancers reported here provides a rich resource for studies of epithelial development and related diseases. Different stages of keratinocyte differentiation
Project description:Loss-of-function mutations in SWI/SNF chromatin remodeling subunit genes are observed in many cancers, but an oncogenic role for SWI/SNF is not well established. Here we reveal that ACTL6A, encoding a SWI/SNF subunit linked to stem and progenitor cell function, is frequently co-amplified and highly expressed together with the p53 family member p63 in head and neck squamous cell carcinoma (HNSCC). ACTL6A and p63 physically interact and cooperatively control a transcriptional program that promotes proliferation and suppresses differentiation, in part through activation of the Hippo-YAP pathway via regulators including WWC1. Consequently, loss of ACTL6A or p63 in tumor cells induces YAP phosphorylation and inactivation, associated with growth arrest and terminal differentiation, all phenocopied by WWC1 overexpression. In vivo, ectopic ACTLC6A/p63 expression promotes tumorigenesis, while ACTL6A expression and YAP activation are highly correlated in primary HNSCC and predict poor patient survival. Thus, ACTL6A and p63 collaborate as oncogenic drivers in HNSCC.
Project description:KMT2D plays a critical role in the control of epithelial enhancers and p63 target gene expression, including the re-quirement of KMT2D for the maintenance of epithelial progenitor gene expression and the coordination of proper terminal differentiation.
Project description:Experiment to determine the genome-wide distribution of P63 binding regions, using an antibody specific to the alpha sub-unit, in mouse (E13.5/E14.5) secondary palatal shelf tissue.
Project description:Using tiled microarrays covering the entire human genome, we identify ~5800 target sites for p63, a homolog of the p53 tumor suppressor essential for stratified epithelial development and implicated in epithelial stem cell maintenance. Keywords: ChIP-chip