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Updated: Oct 3, 2025
10:54
Studying Proteolysis of Cyclin B at the Single Cell Level in Whole Cell Populations
Published on: September 17, 2012
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Quantitative profiling of adaptation to cyclin E overproduction.
Juanita C Limas1, Amiee N Littlejohn2, Amy M House2
1Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Life Science Alliance
|February 17, 2022
Summary
Cells adapt to toxic cyclin E overproduction by down-regulating G1 genes, showing non-genetic adaptation. This reveals how cancer cells tolerate oncogene overexpression and CDK regulation of DNA replication.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Cyclin E/CDK2 complex regulates G1 to S phase cell cycle transition.
- Cyclin E gene overexpression is observed in various cancers, despite its toxicity.
- Understanding cellular tolerance to cyclin E overexpression is crucial for cancer biology.
Purpose of the Study:
- To investigate how non-transformed epithelial cells tolerate chronic cyclin E overproduction.
- To elucidate the mechanisms underlying cellular adaptation to oncogene overexpression.
- To explore the relationship between cyclin E/CDK activity and DNA replication licensing.
Main Methods:
- Chronic cyclin E overproduction in non-transformed epithelial cells.
- Analysis of cell cycle dynamics, CDK activity, and DNA replication.
- Transcriptome analysis to identify gene expression changes.
- Assessment of adaptation reversibility upon cyclin E withdrawal.
Main Results:
- Cells overproducing cyclin E exhibited truncated G1 phases, replication stress, and impaired proliferation.
- Significant intercellular heterogeneity in cell cycle dynamics and CDK activity was observed.
- Adapted cells showed down-regulation of G1-regulated genes and partial resistance to cyclin E withdrawal.
- Evidence suggests cyclin E/CDK inhibits origin licensing indirectly via premature S phase onset.
Conclusions:
- Mammalian cells can adapt to chronic cyclin E overproduction through both genetic and non-genetic mechanisms.
- Cyclin E/CDK plays an inhibitory role in origin licensing, mediated by premature S phase entry.
- This study offers insights into oncogene adaptation, potentially mirroring tumorigenesis processes.
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