Identification of a critical regulatory site in the human interleukin-3 promoter by in vivo footprinting

Scott Cameron, Douglas S. Taylor, Elizabeth C. TePas, Nancy A. Speck, Bernard Mathey-Prevot

Research output: Contribution to journalArticle

59 Scopus citations

Abstract

Interleukin-3 (IL-3) is involved in proliferation and differentiation of hematopoietic progenitor cells. Its expression is subject to precise, tissue- specific regulation, and has been studied extensively in the gibbon T-cell line MLA 144 by a combination of functional assays and DNA binding experiments. To extend these studies, the gibbon IL-3 promoter was cloned and in vivo footprinting of the gibbon and human IL-3 proximal promoters was performed. The gibbon IL-3 promoter was found to be highly homologous to its human counterpart and both promoters yielded identical in vivo footprints after induction of IL-3 synthesis. In particular, we observed specific protection of three guanines over a core sequence TGTGGTTT (IF-1(IL3)) that had not been recognized in previous studies. IF-1(IL3) is not found in other cytokine promoters, but it is conserved in the IL-3 promoter of several species and is similar to a recurring motif in viral and T-cell-specific cellular enhancers. IF-1(IL3) binds a specific complex in MLA 144 and Jurkat nuclear extracts in vitro, which shares the same specificity as the complex bound by the polyoma virus and T-cell receptor δ enhancers. Mutation of the three guanines in IF-1(IL3) core sequence disrupts binding in vitro and abrogates the ability of the IL-3 promoter to mediate inducible expression in T cells. Although IF-1(IL3) is necessary for IL-3 expression, it is not sufficient: a truncated IL-3 promoter with an intact IF-1(IL3) site but no other activator sites is transcriptionally silent. These studies describe a new regulatory element within the IL-3 promoter that is essential for expression and conserved between species.

Original languageEnglish (US)
Pages (from-to)2851-2859
Number of pages9
JournalBlood
Volume83
Issue number10
StatePublished - May 15 1994
Externally publishedYes

ASJC Scopus subject areas

  • Hematology

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    Cameron, S., Taylor, D. S., TePas, E. C., Speck, N. A., & Mathey-Prevot, B. (1994). Identification of a critical regulatory site in the human interleukin-3 promoter by in vivo footprinting. Blood, 83(10), 2851-2859.