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E-cadherin is a WT1 target gene
S Hosono1, I Gross, M A English
1Derald H. Ruttenberg Cancer Center, Mount Sinai School of Medicine, New York, New York 10029, USA.
Abstract:
The WT1 tumor suppressor gene encodes a transcription factor that can activate and repress gene expression. Transcriptional targets relevant for the growth suppression functions of WT1 are poorly understood. We found that mesenchymal NIH 3T3 fibroblasts stably expressing WT1 exhibit growth suppression and features of epithelial differentiation including up-regulation of E-cadherin mRNA. Acute expression of WT1 in NIH 3T3 fibroblasts after retroviral infection induced murine E-cadherin expression. In transient transfection experiments, the human and murine E-cadherin promoters were activated by co-expression of WT1. E-cadherin promoter activity was increased in cells overexpressing WT1 and was blocked by a dominant negative form of WT1. WT1 activated the murine E-cadherin promoter through a conserved GC-rich sequence similar to an EGR-1 binding site as well as through a CAAT box sequence. WT1 produced in vitro or derived from nuclear extracts bound to the WT1-response element within the murine E-cadherin promoter, but not the CAAT box. E-cadherin, a gene important in epithelial differentiation and neoplastic transformation, represents a downstream target gene that links the roles of the WT1 in differentiation and growth control.
Insights
The WT1 tumor suppressor gene promotes epithelial differentiation and growth suppression by up-regulating E-cadherin. This study identifies E-cadherin as a key downstream target linking WT1
Area of Science:
- Molecular Biology
- Cancer Research
- Gene Regulation
Background:
- The WT1 (Wilms Tumor 1) gene is a tumor suppressor.
- WT1's role in growth suppression is linked to its transcriptional targets, which are not fully understood.
- WT1's function in differentiation and growth control needs further elucidation.
Purpose of the Study:
- To identify downstream target genes of WT1.
- To investigate the role of WT1 in epithelial differentiation.
- To understand the mechanism by which WT1 regulates E-cadherin.
Main Methods:
- Stable and acute expression of WT1 in NIH 3T3 fibroblasts.
- Retroviral infection for gene expression.
- Transient transfection assays to analyze promoter activity.
- In vitro binding assays to study protein-DNA interactions.
Main Results:
- WT1 expression induced growth suppression and epithelial differentiation features, including E-cadherin upregulation.
- WT1 activated both human and murine E-cadherin promoters.
- WT1 bound to a specific response element in the murine E-cadherin promoter.
Conclusions:
- E-cadherin is a downstream target gene of WT1.
- WT1 links epithelial differentiation and growth control through E-cadherin regulation.
- WT1's function in tumor suppression may involve modulating E-cadherin expression.