A T cell-specific enhancer of the human CD40 ligand gene

Lisa A. Schubert, Randy Q. Cron, Aileen M. Cleary, Michael Brunner, An Song, Li Sheng Lu, Pascale Jullien, Alan M. Krensky, David B. Lewis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

We observed that the human CD40 ligand (CD40L) gene 5′-flanking region conferred weak promoter activity in activated CD4 T cells, suggesting that additional regions are required for optimal CD40L gene transcription. We therefore examined a 3′-flanking segment of the CD40L gene, which contained a putative NF-κB/Rel ciselement, for its ability to enhance CD40L promoter function. This segment augmented CD40L promoter activity in an orientation-independent manner in CD4 T-lineage cells but not in human B cell or monocyte cell lines. Mapping of CD4 T-lineage cell nuclei identified a DNase I-hypersensitive site in the flanking region near the NF-κB/Rel sequence, suggesting a transcriptional regulatory role. This was further supported by truncation analysis and site-directed mutagenesis, which indicated that the CD40L 3′-flanking NF-κB/Rel cis-element was critical for enhancer function. Electrophoretic mobility shift assays showed that the cis-element preferentially bound the p50 form of the NF-κB1 gene contained in human T cell nuclear protein extracts. This binding also appeared to occur in vivo in CD4 T cells based on chromatin immunoprecipitation assays using NF-κB p50-specific antiserum. Together, these results suggest that the CD40L gene 3′-flanking region acts as a T cell-specific classical transcriptional enhancer by a NF-κB p50-dependent mechanism.

Original languageEnglish (US)
Pages (from-to)7386-7395
Number of pages10
JournalJournal of Biological Chemistry
Volume277
Issue number9
DOIs
StatePublished - Mar 1 2002

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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