Project description:iASPP (PPP1R13L) is an evolutionarily conserved regulator of p53 family members. In mice, iASPP deletion in keratin 14-expressing keratinocytes is sufficient to cause detrimental phenotypes with squamous epithelium abnormalities. In human skin, wild-type nuclear iASPP colocalizes with the key squamous differentiation regulatory factor, TP63, and iASPP mutations are associated with abnormalities in skin development. To clarify how iASPP modulates p63 genome occupancy, p63 ChIP-seq data from iASPP WT and iASPP KO primary mouse keratinocytes (MKC) were compared.
Project description:iASPP (PPP1R13L) is an evolutionarily conserved regulator of p53 family members. In mice, iASPP deletion in keratin 14-expressing keratinocytes is sufficient to cause detrimental phenotypes with squamous epithelium abnormalities. In human skin, wild-type nuclear iASPP colocalizes with the key squamous differentiation regulatory factor, TP63, and iASPP mutations also show abnormalities in skin development. To clarify how iASPP influences the keratinocyte transcriptome, iASPP WT and iASPP KO primary mouse keratinocytes (MKC) were compared.
Project description:Keratinocyte skin cancer, comprising cutaneous squamous (cSCC) and basal cell carcinoma, is the most common malignancy in the UK. P53 is frequently mutated in cSCC. iASPP is a key inhibitor of p53 and NF-kB signalling pathways and has been documented as highly expressed in several types of human cancer. We have previously identified an autoregulatory feedback loop between iASPP and p63, which is critical in epidermal homeostasis. We hypothesised a potential role for dysregulation of this axis in the pathogenesis of keratinocyte malignancies. Immunostaining of 116 cSCC clinical samples revealed increased iASPP and ΔNp63 expression but also highlighted a significant alteration of iASPP cellular localisation, with consequent deregulation of its function. Expression patterns, functionality, gene and microRNA expression analysis were further investigated in 10 cSCC cell lines. Our data suggest that whilst direct effects of iASPP and p63 upon each other’s expression are maintained in cSCC, epigenetic dysregulation of the feedback loop occurs at the microRNA level by a novel mechanism controlling p63 expression. We demonstrate that this autoregulatory feedback loop controls cell migration in cSCC by blocking EMT and promoting proliferation, and provides future directions for clinical biomarker and therapeutic target discovery in cutaneous SCC.
Project description:We report here genome wide identification of p63 binding sites in cycling neonatal foreskin keratinocytes using high throughput sequencing of ChIP enriched DNA. Analysis of gene ontology, database mining with integration with publicly available data, reveals a role for p63 in transcriptional regulation of multiple genes genetically linked to cleft palate. In addition, we identify AP-2α, a transcription factor which, when mutated, also results in craniofacial clefting syndrome, as a co-regulator of p63 responsive genes. Examination of p63 binding sites in neonatal foreskin keratinocytes
Project description:Here we integrated multi-omics profiles including transcriptomics, DNA accessibility and capture Hi-C data to explore how p63 shapes local chromatin architecture in skin keratinocytes isolated from EEC syndrome patients. Surprisingly, we observed decreased chromatin accessibility in a number of DNA looping nodes which were co-mediated by p63 and CTCF. Our findings not only identified a new aspect of the bookmark function of p63, but also shed light on the disease mechanism underlined p63 dysfunction. Therefore, we propose p63 as a spatial genome organizer by modulating a subset of DNA loops with CTCF and therefore fine-tuning transcription programs required for skin keratinocytes.
Project description:Transcription factor (TF) p63 is a master regulator playing critical roles in epidermal development and other cellular processes. Our lab’s previous research deciphered a distinct chromatin architecture at p63 bound site in keratinocytes. In order to figure out whether those chromatin modifications already exist before p63 binding, or p63 occupancy contributes to such chromatin marks, we built p63-expressing cell lines. We then obtained p63 bound regions in these overexpressing cell line, and looked at different histone marks at those sites before p63 occupancy. As shown in the results, before p63 binding, the targeting sites have barely detectable histone marks, indicating p63’s capability to approach unmodified chromatins. Moreover, there is no significant difference in chromatin marks between p63 bound sites and unbound sites when no p63 binding happens. Our in vivo findings were confirmed by examining p63 binding to unmodified nucleosomes in vitro, showing that histone modification is not indispensable for p63 binding but binding site positioning on nucleosome does play a role. Overall, our results suggest that histone modifications do not affect p63 binding, and p63 protein can bind to inaccessible, weakly modified chromatin regions in vivo.
Project description:We report here genome wide identification of p63 binding sites in cycling neonatal foreskin keratinocytes using high throughput sequencing of ChIP enriched DNA. Analysis of gene ontology, database mining with integration with publicly available data, reveals a role for p63 in transcriptional regulation of multiple genes genetically linked to cleft palate. In addition, we identify AP-2α, a transcription factor which, when mutated, also results in craniofacial clefting syndrome, as a co-regulator of p63 responsive genes.