Identification of two Wnt-responsive elements in the intron of RING finger protein 43 (RNF43) gene.

RING finger protein 43 (RNF43), an E3-type ubiquitin ligase, is frequently up-regulated in human colorectal cancer. It has been shown that expression of RNF43 is regulated by the Wnt-signaling pathway. However the regulatory region(s) for its transcriptional activation has not been clarified. In thi...

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Autores principales: Norihiko Takahashi, Kiyoshi Yamaguchi, Tsuneo Ikenoue, Tomoaki Fujii, Yoichi Furukawa
Formato: article
Lenguaje:EN
Publicado: Public Library of Science (PLoS) 2014
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Acceso en línea:https://doaj.org/article/b690e06c1873474285a0753fa4c315aa
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Sumario:RING finger protein 43 (RNF43), an E3-type ubiquitin ligase, is frequently up-regulated in human colorectal cancer. It has been shown that expression of RNF43 is regulated by the Wnt-signaling pathway. However the regulatory region(s) for its transcriptional activation has not been clarified. In this study, we have shown for the first time that RNF43 is a direct target of TCF4/β-catenin complex, and that its expression is regulated by a regulatory region containing two Wnt-responsive elements (WREs) in intron2. A reporter gene assay revealed that nucleotide substitutions in the WREs decreased the reporter activity in colon cancer cells, suggesting that both WREs are involved in the transcriptional activation. Knockdown of β-catenin by siRNA suppressed the reporter activity. In addition, ChIP assay showed that both elements associate with TCF4/β-catenin complex in colon cancer cells. These data indicate that expression of RNF43 is regulated by the canonical Wnt/β-catenin pathway through binding of the WREs with TCF4/β-catenin complex. These findings should be useful for the understanding of the regulatory mechanism of RNF43 and may contribute to the clarification of signaling pathways regulated by RNF43.