Project description:Plakoglobin (PG; γ-Catenin, JUP) is a protein with controversial function. First described as a component of intercellular junctions, it has remained unresolved whether this near-ubiquitously expressed protein acts as a genuine transcriptional regulator in adult tissue like its closest relative β-catenin. Here we have mapped the global gene targets of PG by ChIP-chip in differentiating skin keratinocytes. Applying a peak algorithm, over 5’000 high-confidence PG target promoters were identified and 2’000 for β-catenin with an overlap of 38%. Bioinformatics analyses most significantly associated PG target genes with the Wnt signaling pathway as well as relevant pathways for keratinocyte differentiation. Using a combination of wild-type, PG, β-catenin and PG/β-catenin double null keratinocytes, PG was functionally validated as a LEF/TCF-dependent transcriptional regulator. These data challenge the current understanding of Wnt signaling, one of the most important pathways in tissue homeostasis, by identifying PG as a potent LEF/TCF-dependent transcriptional regulator which functionally overlaps with β-catenin.
Project description:Biomechanical cues are instrumental in guiding embryonic development and cell differentiation. Understanding how these physical stimuli translate into transcriptional programs could provide insight into mechanisms underlying mammalian pre-implantation development. Here, we explore this by exerting microenvironmental control over mouse embryonic stem cells (ESCs). Microfluidic encapsulation of ESCs in agarose microgels stabilized the naïve pluripotency network and specifically induced expression of Plakoglobin (Jup), a vertebrate homologue of β-catenin. Indeed, overexpression of Plakoglobin was sufficient to fully re-establish the naïve pluripotency gene regulatory network under metastable pluripotency conditions, as confirmed by single-cell transcriptome profiling. Finally, we found that in the epiblast, Plakoglobin was exclusively expressed at the blastocyst stage in human and mouse embryos – further strengthening the link between Plakoglobin and naïve pluripotency in vivo. Our work reveals Plakoglobin as a mechanosensitive regulator of naïve pluripotency and provides a paradigm to interrogate the effects of volumetric confinement on cell-fate transitions.
Project description:In adult K14Î?NLef1 mouse, the overexpression of â??NLef1, a Ã?-catenin dominat negative, in basal keratinocytes leads to the conversion of hair follicles into multilayered epithelial cysts and ectopic sebaceous gland. â??NLef1 transcriptional activity led to Gata6 overexpression in the pilosebaceous unit in transgenic mice. To uncover direct target genes of Gata6 we performed ChIP-Seq experiments in primary mouse keratinocytes. Examination of Gata6 genomic targets in mouse primary keratinocytes
