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Cell cycle activity and expression of prohibitin mRNA
A J Roskams1, V Friedman, C M Wood
1Laboratory of Molecular Genetics, National Institute on Aging, Baltimore, Maryland 21224.
Abstract:
Prohibitin, a novel intracellular antiproliferative protein, blocks entry into the S phase of the cell division cycle when its mRNA is microinjected into normal fibroblasts or HeLa cells. To learn more about the interaction between prohibitin and the cell cycle, we studied the effect of microinjecting prohibitin mRNA at different points during the transition from G0 to S phase and analyzed prohibitin mRNA and protein levels in different parts of the cell cycle. The antiproliferative activity of microinjected prohibitin mRNA is high in G0/G1 and falls as cells approach S phase. Prohibitin mRNA and protein levels are high in G1, fall with S phase, rise again in G2, and fall in M. Together, these findings suggest that endogenous prohibitin contributes to the control of the G1 to S transition in cycling cells in a complex manner, which involves both a transcriptional and posttranslational mechanism.
Insights
Prohibitin protein controls cell division by blocking entry into S phase. Its levels and activity vary throughout the cell cycle, suggesting a complex regulatory role in cell proliferation.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Prohibitin is an intracellular protein with antiproliferative properties.
- Its role in regulating the cell division cycle is not fully understood.
Purpose of the Study:
- To investigate the interaction between prohibitin and the cell cycle.
- To determine how prohibitin influences the transition from G0 to S phase.
Main Methods:
- Microinjection of prohibitin mRNA into fibroblasts and HeLa cells at different cell cycle stages.
- Analysis of prohibitin mRNA and protein levels across the cell cycle.
Main Results:
- Microinjected prohibitin mRNA exhibited high antiproliferative activity in G0/G1, decreasing as cells approached S phase.
- Endogenous prohibitin mRNA and protein levels were high in G1, decreased in S phase, increased in G2, and decreased in M phase.
Conclusions:
- Endogenous prohibitin plays a complex role in controlling the G1 to S phase transition.
- This regulation involves both transcriptional and posttranslational mechanisms.