ABSTRACT
The functional diversity of the arterial and venous endothelia is regulated through a complex system of signalling pathways and downstream transcription factors. Here we report that the transcription factor Sox17, which is known as a regulator of endoderm and hemopoietic differentiation, is selectively expressed in arteries, and not in veins, in the mouse embryo and in mouse postnatal retina and adult. Endothelial cell-specific inactivation of Sox17 in the mouse embryo is accompanied by a lack of arterial differentiation and vascular remodelling that results in embryo death in utero. In mouse postnatal retina, abrogation of Sox17 expression in endothelial cells leads to strong vascular hypersprouting, loss of arterial identity and large arteriovenous malformations. Mechanistically, Sox17 acts upstream of the Notch system and downstream of the canonical Wnt system. These data introduce Sox17 as a component of the complex signalling network that orchestrates arterial/venous specification.
Subject(s)
Arteries/metabolism , Endoderm/metabolism , Endothelial Cells/metabolism , HMGB Proteins/metabolism , Morphogenesis/genetics , Retina/metabolism , SOXF Transcription Factors/metabolism , Veins/metabolism , Animals , Arteries/cytology , Cell Differentiation , Cell Proliferation , Embryo, Mammalian , Endoderm/blood supply , Endoderm/cytology , Endothelial Cells/cytology , Gene Expression Regulation, Developmental , HMGB Proteins/genetics , Mice , Neovascularization, Pathologic , Receptors, Notch/genetics , Receptors, Notch/metabolism , Retina/cytology , SOXF Transcription Factors/genetics , Signal Transduction , Veins/cytology , Wnt Proteins/genetics , Wnt Proteins/metabolismABSTRACT
Increased cortical size is essential to the enhanced intellectual capacity of primates during mammalian evolution. The mechanisms that control cortical size are largely unknown. Here, we show that mammalian BAF170, a subunit of the chromatin remodeling complex mSWI/SNF, is an intrinsic factor that controls cortical size. We find that conditional deletion of BAF170 promotes indirect neurogenesis by increasing the pool of intermediate progenitors (IPs) and results in an enlarged cortex, whereas cortex-specific BAF170 overexpression results in the opposite phenotype. Mechanistically, BAF170 competes with BAF155 subunit in the BAF complex, affecting euchromatin structure and thereby modulating the binding efficiency of the Pax6/REST-corepressor complex to Pax6 target genes that regulate the generation of IPs and late cortical progenitors. Our findings reveal a molecular mechanism mediated by the mSWI/SNF chromatin-remodeling complex that controls cortical architecture.
