WT1 targets Gas1 to maintain nephron progenitor cells by modulating FGF signals

• Published in: Development (Cambridge) Vol. 142; no. 7; pp. 1254 - 1266
• Main Authors: Kann, Martin, Bae, Eunnyung, Lenz, Maximilian O, Li, Liangji, Trannguyen, BaoTran, Schumacher, Valerie A, Taglienti, Mary E, Bordeianou, Liliana, Hartwig, Sunny, Rinschen, Markus M, Schermer, Bernhard, Benzing, Thomas, Fan, Chen-Ming, Kreidberg, Jordan A
• Format: Journal Article
• Language: English
• Published: England The Company of Biologists 01.04.2015
• Subjects: Animals; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Proliferation; DNA - genetics; Enzyme Activation - drug effects; Fibroblast Growth Factors - metabolism; Gene Expression Regulation, Developmental; Gene Knockdown Techniques; GPI-Linked Proteins - genetics; GPI-Linked Proteins - metabolism; Mice, Knockout; Models, Animal; Nephrons - abnormalities; Nephrons - embryology; Nephrons - metabolism; Nephrons - pathology; Organ Culture Techniques; Promoter Regions, Genetic - genetics; Protein Binding; Proto-Oncogene Proteins c-akt - metabolism; Proto-Oncogene Proteins c-ret - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; Signal Transduction; Stem Cells - metabolism; Stem Cells and Regeneration; WT1 Proteins - metabolism; Mouse; Nephron progenitor cell; Fibroblast growth factor signaling; Kidney development
• ISSN: 0950-1991; 1477-9129
• DOI: 10.1242/dev.119735

Development of the metanephric kidney depends on tightly regulated interplay between self-renewal and differentiation of a nephron progenitor cell (NPC) pool. Several key factors required for the survival of NPCs have been identified, including fibroblast growth factor (FGF) signaling and the transcription factor Wilms' tumor suppressor 1 (WT1). Here, we present evidence that WT1 modulates FGF signaling by activating the expression of growth arrest-specific 1 (Gas1), a novel WT1 target gene and novel modulator of FGF signaling. We show that WT1 directly binds to a conserved DNA binding motif within the Gas1 promoter and activates Gas1 mRNA transcription in NPCs. We confirm that WT1 is required for Gas1 expression in kidneys in vivo. Loss of function of GAS1 in vivo results in hypoplastic kidneys with reduced nephron mass due to premature depletion of NPCs. Although kidney development in Gas1 knockout mice progresses normally until E15.5, NPCs show decreased rates of proliferation at this stage and are depleted as of E17.5. Lastly, we show that Gas1 is selectively required for FGF-stimulated AKT signaling in vitro. In summary, our data suggest a model in which WT1 modulates receptor tyrosine kinase signaling in NPCs by directing the expression of Gas1.