Differential regulation of intestinal alkaline phosphatase gene expression by Cdx1 and Cdx2

• DOI: 10.1152/ajpgi.00037.2005
• Publication Date: 2005-03-18T04:56:56Z
• Authors: Fuad Alkhoury; Madhu S. Malo; Moushumi Mozumder; Golam Mostafa; Richard A. Hodin
• Keywords: CDX2; Response element

We have examined the role that caudal-related homeobox transcription factors Cdx1 and Cdx2 play in activating enterocyte differentiation marker gene intestinal alkaline phosphatase (IAP). Human colon cancer Caco-2 cells were transiently transfected with and/or Cdx2, semiquantitative RT-PCR was used to study effects on IAP mRNA expression. Transfections a variety of IAP-luciferase reporter constructs identify Cdx response element located within human promoter. Protein-DNA interactions by EMSA. Results showed markedly induced expression, whereas did not, and, fact, inhibited effects. Functional analysis revealed transactivates (fourfold, P < 0.05) promoter through novel (GTTTAGA) between -2369 -2375 upstream translational start site. EMSA both could bind cis element, but cotransfection experiments, approximately 50%. Thus we identified previously unrecognized interaction two important gut factors, context regulation. activates via inhibits