Control of differentiation-induced calbindin-D9k gene expression in Caco-2 cells by cdx-2 and HNF-1α

Liyong Wang, Anna Klopot, Jean Noel Freund, Lauren N. Dowling, Stephen B. Krasinski, James C. Fleet

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Calbindin D9k (CaBP) is critical for intestinal calcium absorption; its in vivo expression is restricted to differentiated enterocytes of the small intestine. Our goal was to identify factors controlling the transcriptional regulation of this gene in the human intestine. Both the natural gene and a 4600-bp promoter construct were strongly regulated by differentiation (> 100-fold) but not by treatment with 1,25(OH)2 vitamin D (<2-fold) in the Caco-2 clone TC7. Deletion-mutation studies revealed that conserved promoter sequences for cdx-2 (at -3158 bp) and hepatocyte nuclear factor (HNF)-1 (at -3131 and at -98 bp) combined to control CaBP expression during differentiation. Other putative response elements were not important for CaBP regulation in TC7 cells (CCAAT enhancer binding protein, pancreatic duodenal homebox-1 (pdx-1), a proximal cdx-2 element). Mutation of the distal HNF-1 site had the greatest impact on CaBP gene expression through disruption of HNF-1α binding; both basal and differentiation-mediated CaBP expression was reduced by 80%. In contrast, mutation of the distal cdx-2 element reduced only basal CaBP expression. Whereas a 60% reduction of CaBP mRNA in the duodenum of HNF-1α null mice confirmed the physiological importance of HNF-1α for CaBP gene regulation, additional studies showed that maximal CaBP expression requires the presence of both HNF-1α and cdx-2. Our data suggest that cdx-2 is a permissive factor that influences basal CaBP expression in enterocytes and that HNF-1α modulates CaBP gene expression during cellular differentiation.

Original languageEnglish (US)
Pages (from-to)G943-G953
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume287
Issue number5 50-5
DOIs
StatePublished - Nov 2004

Keywords

  • 1,25 dihydroxyvitamin D
  • Enterocyte
  • Intestine

ASJC Scopus subject areas

  • Gastroenterology
  • Physiology

Fingerprint Dive into the research topics of 'Control of differentiation-induced calbindin-D<sub>9k</sub> gene expression in Caco-2 cells by cdx-2 and HNF-1α'. Together they form a unique fingerprint.

  • Cite this