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A genomewide oscillation in transcription gates DNA replication and cell cycle
Robert R Klevecz1, James Bolen, Gerald Forrest
1Dynamics Group, Department of Biology, Beckman Research Institute of the City of Hope Medical Center, Duarte, CA 91010, USA.
Summary
Yeast cells exhibit a genomewide transcriptional oscillation, with most genes expressed during the reductive phase. This cycle regulates DNA replication, potentially minimizing oxidative damage.
Area of Science:
- Molecular Biology
- Cell Cycle Regulation
- Yeast Genetics
Background:
- Cellular processes, including transcription and DNA replication, are often regulated by cyclical events.
- Understanding these cycles is crucial for deciphering gene expression patterns and cellular functions.
Purpose of the Study:
- To investigate genomewide transcriptional oscillations in a synchronized yeast culture.
- To determine the relationship between transcriptional patterns, cellular respiration/reduction phases, and DNA replication.
Main Methods:
- Utilized microarray analysis on a yeast continuous synchrony culture system.
- Analyzed transcript levels across a ~40-minute cell cycle.
Main Results:
- Identified a genomewide transcriptional oscillation with three peaks in transcript levels within the ~40-minute cycle.
- Found that the majority of genes (4,679/5,329) were maximally expressed during the reductive phase, while a smaller cluster (650) peaked during the respiratory phase.
- Demonstrated that transcription is organized into redox-state superclusters, with respiration- and reduction-related genes synthesized in opposing phases.
- Observed that the transcriptional cycle gates synchronous DNA replication bursts every 40 minutes.
Conclusions:
- The yeast cell cycle features a coordinated transcriptional oscillation linked to redox states.
- DNA replication is restricted to the reductive phase, suggesting an evolutionary mechanism to protect DNA from oxidative damage during replication.