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Updated: Jun 12, 2026
12:02
Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols
Published on: June 6, 2017
Sequential counteracting kinases restrict an asymmetric gene expression program to early G1
1Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208, USA.
Molecular Biology of the Cell
|June 25, 2010
Summary
Budding yeast Ace2 transcription factor activity is tightly controlled. Cyclin-dependent kinases (CDKs) inactivate Ace2, ensuring gene expression occurs only once per cell cycle.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Gene expression requires precise temporal control of transcription factors.
- In budding yeast, Ace2 transcription factor activity is restricted to daughter cells at the M-to-G1 transition.
- The kinase Cbk1 activates Ace2, but its inactivation mechanism remains unclear.
Purpose of the Study:
- To elucidate the mechanism of Ace2 transcription factor inactivation.
- To understand how Ace2 nuclear export and cytoplasmic sequestration are regulated.
- To identify the factors responsible for limiting Ace2 activity to a specific cell cycle phase.
Main Methods:
- Investigated Ace2 nuclear localization and phosphorylation in response to Cbk1 inhibition.
- Analyzed Ace2 interaction with G1 Cyclin-dependent kinases (CDKs) Pho85 and Cdc28.
- Utilized genetic and biochemical approaches to study Ace2 regulation.
Main Results:
- Ace2 nuclear localization depends on continuous Cbk1 activity; Cbk1 inhibition causes rapid dephosphorylation and cytoplasmic export.
- Ace2, once exported, cannot re-enter the nucleus for the rest of the cell cycle.
- Two redundant mechanisms ensure Ace2 cytoplasmic sequestration: phosphorylation by G1 CDKs and a Pho85-mediated, kinase-independent mechanism.
Conclusions:
- Sequential opposing kinases regulate Ace2 activity, restricting a daughter cell-specific transcriptional program to a narrow window.
- Cyclin-dependent kinases (CDKs) function as cytoplasmic sequestration factors for Ace2.
- This study reveals a novel mechanism for cell cycle-specific gene expression control.
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