Transcriptional Activity of the Distal CD40 Ligand Promoter

• Published in: Biochemical and biophysical research communications Vol. 279; no. 1; pp. 245 - 250
• Main Authors: Lobo, Francis M., Xu, Shuhua, Lee, Celine, Fuleihan, Ramsay L.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 09-12-2000
• Subjects: Base Sequence; CD154 antigen; CD40 ligand; CD40 Ligand - genetics; CD40L protein; Cyclosporine - pharmacology; cytokine; DNA Primers; DNA-Binding Proteins - metabolism; gene expression; Genes, Reporter; Humans; Jurkat Cells; NF-AT; NF-AT protein; NFATC Transcription Factors; Nuclear Proteins; Promoter Regions, Genetic; Protein Binding; T lymphocyte; Transcription Factors - metabolism; Transcription, Genetic; cytokine; NF-AT; T lymphocyte; CD40 ligand; gene expression
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.2000.3914

CD40 ligand (CD40L, CD154) is a T cell cytokine with highly regulated expression that requires the transcription factor nuclear factor of activated T cells (NF-AT) to bind at two sites in the proximal CD40L promoter. We have determined that the distal CD40L promoter (−500 to −1300 bp from start of transcription) conveys superior promoter activity in reporter gene assays. Within the distal promoter, we have identified a third NF-AT binding site, at −761 to −756. Oligonucleotides incorporating each of the three NF-AT sites cross-compete for binding of nuclear extracts from activated T cells and bind NF-ATc2 by antibody supershift. Mutation of the distal NF-AT site reduces activity of the 1300 bp CD40L promoter construct to that of the proximal 500 bp construct, which includes only two NF-AT sites. This suggests that the newly identified NF-AT site is the major mediator of transcriptional activation in the distal CD40L promoter.