https://www.selleckchem.com/products/mlt-748.html Angelman syndrome is a complex neurodevelopmental disorder characterized by delayed development, intellectual disability, speech impairment, and ataxia. It results from the loss of UBE3A protein, an E3 ubiquitin ligase, in neurons of the brain. Despite the dynamic spatiotemporal expression of UBE3A observed in rodents and the potential clinical importance of when and where it is expressed, its expression pattern in humans remains unknown. This reflects a common challenge of studying human neurodevelopment prenatal periods are hard to access experimentally. In this work, human cerebral organoids reveal a change from weak to strong UBE3A in neuronal nuclei within 3 weeks of culture. Angelman syndrome human induced pluripotent stem cell-derived organoids also exhibit early silencing of paternal UBE3A, with topoisomerase inhibitors partially rescuing UBE3A levels and calcium transient phenotypes. This work establishes human cerebral organoids as an important model for studying UBE3A and motivates their broader use in understanding complex neurodevelopmental disorders.Most organs and tissues in the body, including bone, can repair after an injury due to the activation of endogenous adult stem/progenitor cells to replace the damaged tissue. Inherent dysfunctions of the endogenous stem/progenitor cells in skeletal repair disorders are still poorly understood. Here, we report that Fgfr3Y637C/+ over-activating mutation in Prx1-derived skeletal stem/progenitor cells leads to failure of fracture consolidation. We show that periosteal cells (PCs) carrying the Fgfr3Y637C/+ mutation can engage in osteogenic and chondrogenic lineages, but following transplantation do not undergo terminal chondrocyte hypertrophy and transformation into bone causing pseudarthrosis. Instead, Prx1Cre;Fgfr3Y637C/+ PCs give rise to fibrocartilage and fibrosis. Conversely, wild-type PCs transplanted at the fracture site of Prx1Cre;Fgfr3Y637C/+ mice allow