HNF4α and CDX2 Regulate Intestinal YAP1 Promoter Activity

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• The Hippo pathway regulates tissue homeostasis and organ size.
• Yes-associated protein 1 (YAP1) is a key downstream effector, and its dysregulation is linked to cancer and impaired tissue repair.
• Transcriptional regulation of YAP1 in intestinal cells remains poorly understood.

Purpose of the Study:

• To identify gene regulatory regions controlling YAP1 expression in the intestine.
• To pinpoint transcription factors essential for YAP1's intestinal expression.

Main Methods:

• Bioinformatic analysis of chromatin immunoprecipitated DNA (CDX2, HNF4α).
• Reporter assays using YAP1 promoter constructs in Caco-2 and T84 cells.
• In silico analysis, electrophoretic mobility shift assays (EMSA), and chromatin immunoprecipitation (ChIP) experiments.

Main Results:

• A potent intragenic enhancer within the YAP1 gene was identified.
• Bioinformatics and EMSA confirmed binding sites for CDX2 and HNF4α within the enhancer.
• ChIP experiments validated CDX2 and HNF4α binding to the YAP1 enhancer in intestinal cells.

Conclusions:

• A novel enhancer regulating YAP1 promoter activity in intestinal epithelial cells was discovered.
• CDX2 and HNF4α binding to this enhancer are critical for its activity and high YAP1 expression in the intestine.