ESE-1, an Enterocyte-specific Ets Transcription Factor, Regulates MIP-3[alpha] Gene Expression in Caco-2 Human Colonic Epithelial Cells

• Published in: The Journal of biological chemistry Vol. 278; no. 2; pp. 875 - 884
• Main Authors: Kwon, J H, Keates, S, Simeonidis, S, Grall, F, Libermann, T A, Keates, A C
• Format: Journal Article
• Language: English
• Published: 10.01.2003
• ISSN: 0021-9258

We have previously shown that colonic epithelial cells are a major site of MIP-3[alpha] production in human colon and that enterocyte MIP-3[alpha] protein levels are elevated in inflammatory bowel disease. The aim of this study was to determine the molecular mechanisms regulating MIP-3[alpha] gene transcription in Caco-2 intestinal epithelial cells. We show that a [kappa]B element at nucleotides -82 to -93 of the MIP-3[alpha] promoter binds p50/p65 NF-[kappa]B heterodimers and is a major regulator of basal and interleukin-1[beta] (IL-1[beta])-mediated gene activation. Scanning mutagenesis of the MIP-3[alpha] 5'-flanking region also identified two additional binding elements: Site X (nucleotides -63 to -69) and Site Y (nucleotides -143 to -154). Site X (CGCCTTC) bound Sp1 and regulated basal MIP-3[alpha] gene transcription. Overexpression of Sp1 increased basal luciferase activity, whereas, substitutions in the Sp1 element significantly reduced reporter activity. In contrast, Site Y (AAGCAGGAAGTT) regulated both basal and cytokine-induced gene activation and bound the Ets nuclear factor ESE-1. Substitutions in the Site Y element markedly reduced inducible MIP-3[alpha] reporter activity. Conversely, overexpression of ESE-1 significantly up-regulated MIP-3[alpha] luciferase levels. Taken together, our findings demonstrate that co-ordinate activation and binding of ESE-1, Sp1, and NF-[kappa]B to the MIP-3[alpha] promoter is required for maximal gene expression by cytokine-stimulated Caco-2 human intestinal epithelial cells.