Project description:We demonstrate using conditional mutagenesis that Pbx1, with and without Pbx2+/ sensitization, regulates regional identity and laminar patterning of the developing mouse neocortex in cortical progenitors (Emx1-Cre) and in newly generated neurons (Nex1-Cre). Pbx1/2 mutants have three salient molecular phenotypes of cortical regional and laminar organization: hypoplasia of the frontal cortex, ventral expansion of the dorsomedial cortex, and ventral expansion of Reelin expression in the cortical plate of the frontal cortex, concomitant with an inversion of cortical layering in the rostral cortex. Molecular analyses, including PBX ChIP-seq, provide evidence that PBX promotes frontal cortex identity by repressing genes that promote dorsocaudal fate. Chromatin immunoprecipitation was performed using antibody against Pbx1/2/3/ (sc-888, Santa Cruz). Wild type E12.5 mouse whole cortex was used for the analysis.
Project description:We demonstrate using conditional mutagenesis that Pbx1, with and without Pbx2+/ sensitization, regulates regional identity and laminar patterning of the developing mouse neocortex in cortical progenitors (Emx1-Cre) and in newly generated neurons (Nex1-Cre). Pbx1/2 mutants have three salient molecular phenotypes of cortical regional and laminar organization: hypoplasia of the frontal cortex, ventral expansion of the dorsomedial cortex, and ventral expansion of Reelin expression in the cortical plate of the frontal cortex, concomitant with an inversion of cortical layering in the rostral cortex. Molecular analyses, including PBX ChIP-seq, provide evidence that PBX promotes frontal cortex identity by repressing genes that promote dorsocaudal fate. Chromatin immunoprecipitation was performed using antibody against Pbx1/2/3 (sc-888, Santa Cruz). Wild type E15.5 mouse whole cortex was used for the analysis.
Project description:Cell type-specific master transcription factors (MTFs) play vital roles in defining cell identity and function. However, the roles ubiquitous factors play in the specification of cell identity remain underappreciated. Here we show that all three subunits of the ubiquitous heterotrimeric CCAAT-binding NF-Y complex are required for the maintenance of embryonic stem cell (ESC) identity, and establish NF-Y as a novel component of the core pluripotency network. Genome-wide occupancy and transcriptomic analyses in ESCs and neurons reveal that not only does NF-Y regulate genes with housekeeping functions through cell type-invariant promoter-proximal binding, but also genes required for cell identity by binding to cell type-specific enhancers with MTFs. Mechanistically, NF-Y's distinctive DNA-binding mode promotes MTF binding at enhancers by facilitating a permissive chromatin conformation. Our studies unearth a novel function for NF-Y in promoting chromatin accessibility, and suggest that other proteins with analogous structural and DNA-binding properties may function in similar ways. Genome-wide mapping of NF-YA, NF-YB, and NF-YC subunits of the NF-Y complex in mouse ESCs, and microarray gene expression profiling of control knockdown (KD), NF-YA KD, NF-YB KD, NF-YC KD, and NF-YA/NF-YB/NF-YC triple KD ESCs.