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Multiple cis-acting elements regulate the expression of the early T cell activation antigen CD69
María del Carmen Castellanos1, Sonia López-Giral, Manuel López-Cabrera
1Servicio de Inmunología, Hospital de la Princesa, UAM, Madrid, Spain.
European Journal of Immunology
|October 18, 2002
Summary
CD69 gene expression in T lymphocytes is induced by mitogenic signals. Its regulation involves multiple DNA elements and transcription factors from the AP-1, EGR, and ATF/CREB families.
Area of Science:
- Immunology
- Molecular Biology
- Cellular Biology
Background:
- CD69 is an early activation antigen on T lymphocytes.
- Its expression is triggered by T cell receptor (TCR) stimulation or mimicry.
Purpose of the Study:
- To investigate the molecular mechanisms regulating CD69 gene induction.
- To identify specific DNA elements and transcription factors involved in CD69 expression.
Main Methods:
- Jurkat cells were treated with phorbol ester (PMA) and calcium ionophore.
- Promoter analysis and mutagenesis of the CD69 gene promoter (-78 to +16).
- Electrophoretic mobility shift assays (EMSA) to identify protein-DNA interactions.
Main Results:
- PMA and calcium ionophore synergistically induced CD69 expression and promoter activity, inhibited by cyclosporin A (CsA).
- Mutagenesis of AP-1 motifs did not affect basal or inducible promoter activity.
- Novel inducible complexes involving Egr-1/Egr-3, Egr-1, and ATF-3/Fos were identified.
- Mutation of individual binding sites partially reduced basal activity, while combined mutations significantly reduced inducibility.
Conclusions:
- CD69 gene induction by mitogenic signals is controlled by multiple cis-acting elements.
- The interplay of AP-1, EGR, and ATF/CREB family transcription factors regulates CD69 expression.