A T cell-specific enhancer of the human CD40 ligand gene.
J Biol Chem
; 277(9): 7386-95, 2002 Mar 01.
Article
in En
| MEDLINE
| ID: mdl-11751888
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-kappaB/Rel cis-element, 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-kappaB/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-kappaB/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-kappaB1 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-kappaB 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-kappaB p50-dependent mechanism.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Transcription, Genetic
/
T-Lymphocytes
/
Promoter Regions, Genetic
/
CD40 Ligand
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
J Biol Chem
Year:
2002
Document type:
Article
Affiliation country:
United States