Paired Box 9 (PAX9), the RNA polymerase II transcription factor, regulates human ribosome biogenesis and craniofacial development (RNAPII ChIP-seq)
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ABSTRACT: Paired Box 9 (PAX9), the RNA polymerase II transcription factor, regulates human ribosome biogenesis and craniofacial development (RNAPII ChIP-seq)
Project description:We investigated the role of Paired Box 9 in regulating the transcription of mRNAs required for human ribosome biogenesis and craniofacial development.
Project description:We investigated the role of Paired Box 9 in regulating the transcription of mRNAs required for human ribosome biogenesis and craniofacial development.
Project description:Paired Box 9 (PAX9), the RNA polymerase II transcription factor, regulates human ribosome biogenesis and craniofacial development (RNA-seq)
Project description:Small cell lung cancer (SCLC) is a more aggressive and deadlier form of lung cancer with limited effective therapies currently available. By utilizing a genome-wide CRISPR-Cas9 dropout screen, we have identified the Paired box protein 9 (PAX9) as an essential factor for the cell viability of SCLC-A type, which accounts for approximately 70% of all SCLC. PAX9 is transcriptionally driven by the BAP1/ASXL3/BRD4 epigenetic axis and is overexpressed in human malignant SCLC tumor samples. Genome-wide studies have revealed that PAX9 occupies distal enhancer elements and represses gene expression by restricting enhancer activity. Genetic depletion of PAX9 leads to a dramatic induction of a primed-active enhancer transition, resulting in an increased expression of a large number of neural differentiation and tumor-suppressive genes in multiple SCLC cell lines. Mechanistically, PAX9 interacts and co-functions with the Nucleosome Remodeling and Deacetylase (NuRD) complex at enhancers and they repress the nearby gene expression, which could be rescued by pharmacological HDAC inhibition. Overall, this study provides mechanistic insight into the oncogenic function of the PAX9/NuRD complex epigenetic axis in human SCLC and suggests that re-activation of the primed enhancers may have therapeutic efficacy in treating SCLC-A type cancers expressing high levels of PAX9.
Project description:Pax1 and Pax9 play redundant, synergistic functions in the patterning and differentiation of the sclerotomal cells that give rise to the vertebral bodies and intervertebral discs (IVD) of the axial skeleton. Gene expression profiling of an enriched population of Pax1/Pax9-expressing cells of the embryonic IVD revealed that Pax1 and Pax9 regulate cell proliferation, cartilage development, collagen fibrillogenesis and other processes vital in early IVD morphogenesis. Twenty-nine of the Pax1/Pax9 targets are also associated with axial skeletal defects that phenocopy Pax1/Pax9-deficient mice. Pax1 likely auto-regulates itself and is up-regulated in the absence of Pax9, clarifying how it compensates for the loss of Pax9, while Pax9 is unaffected by the loss of Pax1. Pax1 and Pax9 positively regulate several of the cartilage development genes known to be regulated by the “Sox trio” (Sox5/Sox6/Sox9).
Project description:The aim of this study was to identify differentially expressed genes within the pharyngeal arches of Pax9-null embryos at E9.5. Mice null for Pax9 die in the neonatal period with complex cardiovascular defects, caused by abnormal morphogenesis of the pharyngeal arch arteries.