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G2-seq: A High Throughput Sequencing-based Technique for Identifying Late Replicating Regions of the Genome
Published on: March 22, 2018
G2 checkpoint targets late replicating DNA
Del Campo1, R Samaniego, J F Giménez-Abián
1Centro de Investigaciones Biológicas, CSIC. Velázquez, 144. E-28006- Madrid, Spain.
Biology of the Cell
|November 25, 2003
Summary
Cell cycle synchronization in multinucleate cells relies on a checkpoint mechanism. Late replicating DNA modifications allow cells to bypass this checkpoint, enabling simultaneous mitosis.
Area of Science:
- Cell Biology
- Molecular Biology
- Plant Science
Background:
- Multinucleate cells in Allium cepa exhibit synchronized nuclear division despite asynchronous DNA replication.
- Advanced nuclei replicate earlier but have a longer G2 phase than delayed nuclei.
Purpose of the Study:
- To elucidate the checkpoint mechanism synchronizing nuclear division in multinucleate cells.
- To investigate the role of late replicating DNA in this synchronization process.
Main Methods:
- Induction of multinucleate cells in Allium cepa meristems.
- In vivo 5-aminouracil feeding to inhibit DNA replication in delayed nuclei.
- Bromosubstitution followed by anoxic UVA irradiation of DNA.
Main Results:
- Replication inhibition in delayed nuclei caused metaphase delay in advanced nuclei, indicating a checkpoint.
- Some delayed nuclei adapted and entered mitosis with chromatid damage.
- Modifying late replicating DNA in advanced nuclei by bromosubstitution and irradiation bypassed the checkpoint, preventing metaphase delay.
Conclusions:
- A checkpoint mechanism synchronizes mitosis in multinucleate cells by sensing replication status.
- Late replicating DNA sequences are targets of the checkpoint signal.
- Bypassing the checkpoint through specific DNA modifications allows entry into mitosis despite replication asynchrony.
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