TY - JOUR

T1 - Differentiation-dependent activation of the human intestinal alkaline phosphatase promoter by HNF-4 in intestinal cells.

AU - Olsen, Line

AU - Bressendorff, Simon

AU - Troelsen, Jesper T

AU - Olsen, Jørgen

N1 - Keywords: Alkaline Phosphatase; Antigens, Neoplasm; Binding Sites; Caco-2 Cells; Cell Differentiation; DNA-Binding Proteins; Enterocytes; Gene Expression Regulation, Enzymologic; Hela Cells; Hepatocyte Nuclear Factor 4; Humans; Luciferases; Mutagenesis, Site-Directed; Phosphoproteins; Promoter Regions (Genetics); Trans-Activation (Genetics); Transcription Factors; Transfection

PY - 2005

Y1 - 2005

N2 - The intestinal alkaline phosphatase gene (ALPI) encodes a digestive brush-border enzyme, which is highly upregulated during small intestinal epithelial cell differentiation. To identify new putative promoter motifs responsible for the regulation of ALPI expression during differentiation of the enterocytes, we have conducted a computer-assisted cis-element search of the proximal human ALPI promoter sequence. A putative recognition site for the transcription factor hepatocyte nuclear factor (HNF)-4 was predicted at the positions from -94 to -82 in relation to the translational start site. The ability of HNF-4alpha to stimulate the expression from the ALPI promoter was investigated in the nonintestinal Hela cell line. Cotransfection with an HNF-4alpha expression vector demonstrated a direct activation of the ALPI promoter through this -94 to -82 element. EMSA showed that HNF-4alpha from nuclear extracts of differentiated intestinal epithelial cells (Caco-2) bound with high affinity to the predicted HNF-4 binding site. A 521 bp promoter fragment containing the HNF-4 binding site demonstrated a differentiation-dependent increase in promoter activity in Caco-2 cells. The presence of the HNF-4 binding site was necessary for this increase to occur.

AB - The intestinal alkaline phosphatase gene (ALPI) encodes a digestive brush-border enzyme, which is highly upregulated during small intestinal epithelial cell differentiation. To identify new putative promoter motifs responsible for the regulation of ALPI expression during differentiation of the enterocytes, we have conducted a computer-assisted cis-element search of the proximal human ALPI promoter sequence. A putative recognition site for the transcription factor hepatocyte nuclear factor (HNF)-4 was predicted at the positions from -94 to -82 in relation to the translational start site. The ability of HNF-4alpha to stimulate the expression from the ALPI promoter was investigated in the nonintestinal Hela cell line. Cotransfection with an HNF-4alpha expression vector demonstrated a direct activation of the ALPI promoter through this -94 to -82 element. EMSA showed that HNF-4alpha from nuclear extracts of differentiated intestinal epithelial cells (Caco-2) bound with high affinity to the predicted HNF-4 binding site. A 521 bp promoter fragment containing the HNF-4 binding site demonstrated a differentiation-dependent increase in promoter activity in Caco-2 cells. The presence of the HNF-4 binding site was necessary for this increase to occur.

U2 - 10.1152/ajpgi.00449.2004

DO - 10.1152/ajpgi.00449.2004

M3 - Journal article

C2 - 15831710

VL - 289

SP - G220-6

JO - American Journal of Physiology: Gastrointestinal and Liver Physiology

JF - American Journal of Physiology: Gastrointestinal and Liver Physiology

SN - 0193-1857

IS - 2

ER -