Cdc14 phosphatase: warning, no delay allowed for chromosome segregation!

Area of Science:

• Cell Biology
• Genetics
• Molecular Biology

Background:

• The cell cycle involves coordinated progression driven by cyclin-dependent kinases (CDKs) and regulated by phosphatases.
• While CDK inhibition is a cancer research focus, the role of phosphatases in cell cycle termination is less understood.
• Cdc14 is a master cell cycle phosphatase in Saccharomyces cerevisiae, crucial for cell cycle progression.

Purpose of the Study:

• To investigate the consequences of transiently inactivating the master cell cycle phosphatase Cdc14.
• To determine the impact of Cdc14 inactivation at specific cell cycle stages, particularly anaphase.
• To extend the analysis to diploid yeast cells and assess effects on genome integrity.

Main Methods:

• Transient inactivation of the Cdc14 phosphatase in Saccharomyces cerevisiae.
• Analysis of cell cycle progression and chromosome segregation.
• Examination of anaphase bridge formation and cytokinesis.
• Studies in both haploid and diploid yeast cells, including hybrid diploids.

Main Results:

• Transient Cdc14 inactivation during anaphase irreversibly impairs segregation of ribosomal DNA regions, forming anaphase bridges (ABs).
• Cytokinesis severs the ABs, resulting in genetically compromised daughter cells.
• Analysis in diploid cells revealed more dramatic consequences for genome integrity compared to haploid cells.

Conclusions:

• The timing of Cdc14 inactivation is critical, with anaphase inactivation causing severe genome instability.
• The study highlights the essential role of phosphatases in ensuring accurate cell division and maintaining genome integrity.
• Diploid cells exhibit heightened sensitivity to Cdc14 inactivation, underscoring its importance in complex genomes.