SWI/SNF chromatin remodelers target enhancers via interaction with Eya1 and Six2 to specify metanephric fate and maintain nephron progenitor pool

Eya1 is a critical regulator for establishing nephron fate and acts upstream of Six2. However, how Eya1-centered network operates remains elusive. Here we identified Eya1's interacting factors via mass-spectrometry and show that Eya1 and Six2 interact with Brg1-based SWI/SNF chromatin-remodeling complex in the kidney. Brg1 specifies the nephron fate and regulates Eya1 expression through binding to multiple cis-regulatory-elements. In the nephron-progenitors, Brg1/Six2 co-occupy cis-regulatory-elements at key loci and Brg1-recruitment to many of these regions is disrupted in the absence of Six2. We demonstrate Six2-dependent Brg1-occupancy to Mycn promoter and two distal enhancers of Pbx1, all of which direct nephron-progenitor-specific expression in response to binding to Six2. RNA-seq analysis reveals that depletion of Brg1 leads to upregulation of genes for podocyte-lineages and aberrant activation of cell-death inducing factors. Together, this study highlights an essential function of the Brg1-BAFs in cooperation with Eya1/Six2 in enhancer-mediated regulation of gene expression in the nephron-progenitors. We sequenced RNA isolated from kidney FACS-purified from control and Brg1-cKO conditions.