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Homeodomain protein CDX2 regulates goblet-specific MUC2 gene expression
Hiroshi Yamamoto1, Yun Qing Bai, Yasuhito Yuasa
1Department of Molecular Oncology, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
Biochemical and Biophysical Research Communications
|February 1, 2003
Summary
CDX2 protein activates the MUC2 gene, crucial for intestinal goblet cell differentiation. This study identifies CDX2 as a key regulator of MUC2 transcription, unlike CDX1.
Area of Science:
- Gastroenterology
- Molecular Biology
- Cell Biology
Background:
- Intestinal mucin MUC2 is vital for the protective mucus layer, primarily produced by goblet cells.
- Goblet cell differentiation and MUC2 expression are tightly regulated processes in the intestine.
Purpose of the Study:
- To identify transcriptional activators controlling goblet-specific MUC2 gene expression.
- To investigate the role of homeodomain proteins CDX1 and CDX2 in MUC2 regulation.
Main Methods:
- Transient transfection of COS-7 cells with CDX1 or CDX2 expression constructs.
- Luciferase assay to measure MUC2 promoter activity.
- Reverse transcription-polymerase chain reaction (RT-PCR) for MUC2 mRNA levels.
- Electrophoretic mobility shift assay (EMSA) to assess protein-DNA binding.
Main Results:
- CDX2 expression activated the MUC2 promoter and increased MUC2 mRNA levels.
- CDX1 expression did not affect MUC2 promoter activity or mRNA levels.
- EMSA confirmed direct binding of CDX2 to the MUC2 promoter cis element (MUC2-WT).
Conclusions:
- CDX2, but not CDX1, directly interacts with the MUC2 promoter to activate its transcription.
- CDX2 plays a significant role in regulating MUC2 expression and goblet cell differentiation.