HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 292/2/G535    most recent 00385.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Yan, Y. Articles by Merlin, D. Search for Related Content PubMed PubMed Citation Articles by Yan, Y. Articles by Merlin, D.

MUCOSAL BIOLOGY

Characterization of the human intestinal CD98 promoter and its regulation by interferon-

Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia

Submitted 18 August 2006 ; accepted in final form 26 September 2006

Growing evidence that epithelial CD98 plays an important role in intestinal inflammation focused our interest to investigate the transcriptional regulation of CD98. Our mouse-based in vivo and in vitro experiments revealed that epithelial colonic CD98 mRNA expression was transcriptionally increased in intestinal inflammation. We then isolated and characterized a 5'-flanking fragment containing the promoter region required for CD98 gene transcription. Primer extension and rapid amplification of 5'-cDNA ends were used to map a transcriptional initiation site 129 bp upstream from the translational start codon (ATG). Direct sequencing of the 5'-flanking region revealed the presence of four GC-rich stimulating protein (Sp)1 binding domains, one NF-B binding domain, and no TATA box. Binding of Sp1 [Sp1(–874), SP1(–386), Sp1(–187), and Sp1(–177)] and NF-B [NF-B(–213)] to the promoter was confirmed by EMSA and supershift assays. Furthermore, chromatin immunoprecipitation experiments showed the in vivo DNA-Sp1 and DNA-NF-B interactions under basal and IFN--stimulated conditions. Reporter genes driven by serially truncated and site-mutated CD98 promoters were used to examine basal and IFN--responsive transcription in transiently transfected Caco2-BBE cells. Our results revealed that Sp1(–187), Sp1(–177), and the NF-B binding site were essential for basal and IFN--stimulated CD98 promoter activities, whereas Sp1(–874) and Sp1(–386) were not. The results from additional site-mutated CD98 promoters suggested that Sp1(–187), Sp1(–177), and the NF-B site may cooperate in mediating basal and IFN--stimulated CD98 promoter activities. Finally, we demonstrated that a reduction of Sp1 or NF-B expression reduced CD98 protein expression in unstimulated and IFN--stimulated Caco2-BBE cells. Collectively, these findings indicate that the Sp1 and NF-B transcription factors are likely to play a significant role in IFN--mediated transcriptional regulation of CD98 in the intestinal epithelium, providing new insights into the regulation of CD98 expression in intestinal inflammation.

Caco2-BBE; mice; promoter; stimulating protein 1; nuclear factor-B

This article has been cited by other articles:

				A. Saha, C. E. Hammond, M. Gooz, and A. J. Smolka The role of Sp1 in IL-1{beta} and H. pylori-mediated regulation of H,K-ATPase gene transcription Am J Physiol Gastrointest Liver Physiol, November 1, 2008; 295(5): G977 - G986. [Abstract] [Full Text] [PDF]