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Loss of transcription factor AP-1 DNA binding activity during lymphocyte aging in vivo
E Sikora1, B Kamińska, E Radziszewska
1Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland.
Abstract:
The main feature of cellular senescence is cessation of cell proliferation. Protooncogene c-fos, which is required for the cell to enter into DNA synthesis, is repressed in senescent fibroblasts. Diminished expression of c-fos and impaired formation of AP-1, which is a complex of c-Fos and c-Jun proteins acting as a transcription factor, was found in lymphocytes derived from old (> 18 months) mice and stimulated with Con A. There were no differences in c-jun expression and formation of other transcription factors (AP-2 and AP-3) between lymphocytes isolated from old and young mice.
Insights
Cellular senescence halts cell proliferation. In old mice, lymphocytes showed reduced c-fos expression and AP-1 transcription factor formation, impacting DNA synthesis.
Area of Science:
- Cellular biology
- Immunology
- Aging research
Background:
- Cellular senescence is characterized by irreversible cell cycle arrest.
- Protooncogene c-fos is crucial for initiating DNA synthesis.
- AP-1 is a transcription factor complex of c-Fos and c-Jun proteins.
Purpose of the Study:
- To investigate the expression of c-fos and the formation of the AP-1 transcription factor in lymphocytes from aged mice.
- To compare these molecular changes with those in lymphocytes from young mice.
Main Methods:
- Lymphocytes were isolated from old (> 18 months) and young mice.
- Cells were stimulated with Concanavalin A (Con A).
- Expression levels of c-fos and c-jun, and formation of AP-1 were analyzed.
Main Results:
- Senescent fibroblasts exhibit repressed c-fos expression.
- Lymphocytes from old mice showed diminished c-fos expression and impaired AP-1 formation after Con A stimulation.
- No significant differences were observed in c-jun expression or the formation of AP-2 and AP-3 transcription factors between old and young mice.
Conclusions:
- Reduced c-fos expression and impaired AP-1 formation in aged lymphocytes may contribute to age-related immune dysfunction.
- These findings highlight specific molecular alterations associated with aging in immune cells.