Chl1 helicase controls replication fork progression by regulating dNTP pools

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Eukaryotic cells possess a replication stress response to manage DNA replication challenges.
• The replication checkpoint protein Mrc1 is crucial for this response, but its interactions are not fully elucidated.

Purpose of the Study:

• To investigate the functional interactions of the replication checkpoint protein Mrc1.
• To elucidate the role of the Chl1 helicase in the replication stress response and DNA replication.

Main Methods:

• Genetic interaction analysis between MRC1 and CHL1.
• Analysis of RNR1 gene expression and dNTP levels.
• Assessment of RPA-coated single-stranded DNA formation.
• Evaluation of checkpoint activation under replication stress conditions.

Main Results:

• MRC1 negatively interacts with CHL1, indicating distinct roles in replication stress response.
• Chl1 loss increases RNR1 expression and dNTP levels without activating DNA damage response.
• Chl1 deficiency impairs RPA-coated ssDNA formation and subsequent checkpoint activation.
• Chl1 controls replication fork rate under replication stress.

Conclusions:

• Chl1 helicase ensures proper intracellular dNTP levels, controlling replication fork progression under stress.
• Chl1 influences RPA-dependent checkpoint activation by maintaining dNTP homeostasis.
• Distinct roles of Mrc1 and Chl1 in replication fork restart and progression were uncovered.