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Interleukin-1 costimulatory activity on the interleukin-2 promoter via AP-1
K Muegge1, T M Williams, J Kant
1Laboratory of Molecular Immunoregulation, Program Resources Inc., Frederick, MD 21701.
Insights
Interleukin-1 (IL-1) regulates inflammation and immunity by promoting T lymphocyte growth. This involves the transcription factor AP-1, with IL-1 influencing c-jun and antigen influencing c-fos expression.
Area of Science:
- Immunology
- Molecular Biology
- Cellular Signaling
Background:
- Interleukin-1 (IL-1) is a key regulator of inflammatory and immune responses.
- IL-1 acts as a crucial co-stimulatory signal, alongside antigen recognition, for T lymphocyte proliferation.
- Interleukin-2 (IL-2) production is essential for T cell growth.
Purpose of the Study:
- To investigate the molecular mechanisms by which IL-1 enhances T lymphocyte growth.
- To identify the role of the transcription factor AP-1 in mediating IL-1's effects on IL-2 gene expression.
- To elucidate the differential regulation of AP-1 components by IL-1 and antigenic signals.
Main Methods:
- Analysis of the human IL-2 gene promoter region to identify IL-1-responsive elements.
- Examination of messenger RNA (mRNA) expression levels for AP-1 components (c-jun and c-fos) under different stimulation conditions.
- Utilizing techniques to assess transcription factor binding and gene expression modulation.
Main Results:
- An IL-1-responsive element was identified in the IL-2 gene promoter, sharing similarity with the AP-1 binding site.
- IL-1 stimulation led to increased expression of c-jun mRNA.
- Antigenic stimulation resulted in enhanced expression of c-fos mRNA.
Conclusions:
- The transcription factor AP-1 acts as a nuclear mediator for IL-1's diverse cellular actions.
- The components of AP-1, c-jun and c-fos, are independently regulated by distinct signals (IL-1 and antigen, respectively).
- This independent regulation highlights a sophisticated mechanism for controlling T lymphocyte activation and immune responses.
Abstract:
Interleukin-1 (IL-1) is a major regulator of inflammation and immunity. IL-1 induces T lymphocyte growth by acting as a second signal (together with antigen) in enhancing the production of interleukin-2 (IL-2). An IL-1-responsive element in the promoter region of the human IL-2 gene was similar to the binding site for the transcription factor AP-1. IL-1 enhanced expression of c-jun messenger RNA, whereas the antigenic signal enhanced messenger RNA expression of c-fos. Thus, the two components of the AP-1 factor are independently regulated and the AP-1 factor may serve as a nuclear mediator for the many actions of IL-1 on cells.