Genome-wide map of Tcf/Lef transcription factors, ß-catenin, Six2 and chromatin marks in mouse nephron progenitor cells

During embryonic kidney development, nephron progenitor cells (NPCs) self-renew and differentiate into all cells in mature nephrons. The Wnt signaling components Wnt9b and ß-catenin are required for both NPC self-renewal and differentiation. A low level of Wnt/ß-catenin are associated with NPC self-renewal while a high level with differentiation. To investigate the transcriptional mechanisms behind Wnt/ß-catenin-driven regulation of NPCs states, we modeled NPC self-renewal and differentiation in vitro with NPEM (Brown et al., 2015) supplemented with low (1.25 µM) or high (5 µM) concentration of CHIR22091 (CHIR), a small molecule GSK3ß inhibitor that stabilizes ß-catenin. We have found the Tcf/Lef family repressors Tcf7l1 and Tcf7l2 are enriched in low CHIR condition, while the activators Tcf7 and Lef1 in high CHIR condition, correlating with the NPC differentiation program transiting from being repressed to activated. To identify direct transcriptional targets of Tcf/Lef factors and ß-catenin, here we generated ChIP-Seq data from primary NPC, as well as NPC cultured in low and high CHIR concentration. Overall design: ChIP-Seq was performed in primary NPCs, as well as NPCs cultured in low (1.25 µM) CHIR and high (5 µM) CHIR conditions.