Identification of Novel Wilms' Tumor Suppressor Gene Target Genes Implicated in Kidney Development

Abstract

The Wilms' tumor suppressor gene (WT1) encodes a zinc finger transcription factor that is vital during development of several organs including metanephric kidneys. Despite the critical regulatory role of WT1, the pathways and mechanisms by which WT1 orchestrates development remain elusive. To identify WT1 target genes, we performed a genomewide expression profiling analysis in cells expressing inducible WT1. We identified a number of direct WT1 target genes, including the epidermal growth factor (EGF)-family ligands epiregulin and HB-EGF, the chemokine CX3CL1, and the transcription factors SLUG and JUNB. The target genes were validated using quantitative reverse transcriptase-polymerase chain reaction, small interfering RNA knockdowns, chromatin immunoprecipitation, and luciferase reporter analyses. Immunohistochemistry of fetal kidneys confirmed that a number of the WT1 target genes had overlapping expression patterns with the highly restricted spatiotemporal expression of WT1. Finally, using an in vitro embryonic kidney culture assay, we found that the addition of recombinant epiregulin, amphiregulin, CX3CL1, and interleukin-11 significantly enhanced ureteric bud branching morphogenesis. Our genome-wide screen implicates WT1 in the transcriptional regulation of the EGF-family of growth factors as well as the CX3CL1 chemokine during nephrogenesis.

Wilms' Tumor 1 Gene Expression in Hepatocellular Carcinoma Promotes Cell Dedifferentiation and Resistance to Chemotherapy

“…These included albumin, transthyretin, alcohol dehydrogenase, glucose-6-phosphatase, DHEA sulfotransferase (SULT2A1), the EGFR, and HNF4 (38,39). Although some of the differentially expressed genes, such as Ereg, H19, CTGF, Egr1, and the EGFR, are recognized transcriptional targets of WT1 (1,8,40,41), most of the genes identified in our study have not been functionally linked to WT1, and therefore may be indirect targets of this transcription factor. Indeed, many of the modified genes upon WT1 silencing were transcription factors such as Egr1, ID1, PEA3, and DEC1, the alteration of which may effect on a wide range of target genes.…”

Non-canonical HIF-2α function drives autonomous breast cancer cell growth via an AREG–EGFR/ErbB4 autocrine loop

“…While the HIF-2a-dependent enrichment of the AREG promoter in ChIP experiments reveals direct recruitment of the transcription factor to the larger regulatory region, it remains unclear if direct DNA binding of HIF-2a to the WRE is involved. HIF2a ChIP experiments showed hypoxically induced chromatin enrichment of the known WRE-dependent heparin-binding EGF-like growth factor (HBEGF) gene, which had been identified in a genome-wide screen for novel WT-1 targets along with AREG (Kim et al, 2007), suggesting that the HIF-2a/WRE interplay might involve a more general mechanism (DPS and RHW, unpublished data).…”

WT1 controls antagonistic FGF and BMP-pSMAD pathways in early renal progenitors

“…Genes associated with WT1-ChIP peaks exhibit expression patterns (according to GUDMAP (www.gudmap.org 19 ) and Eurexpress (www.eurexpress.org) databases) overlapping with that of Wt1 with a proportion of targets showing restriction to the early MM (for example, Hoxb1; P ¼ 9.99e À 80; Bonferroni corrected P-value), the renal vesicle (for example, Heyl; P ¼ 3.51e À 32; Bonferroni corrected P-value) or podocytes (for example, Pard6B; P ¼ 7.01e À 95; Bonferroni corrected P-value). Comparison of peak-associated genes with molecular signature databases (MSigDB) revealed as top hit a gene set found to be induced upon WT1 expression 20 ( Supplementary Fig. 1C).…”