Cdc14A and Cdc14B Redundantly Regulate DNA Double-Strand Break Repair

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Cdc14 phosphatases regulate cell division in yeast.
• Mammalian Cdc14A and Cdc14B are implicated in DNA damage repair, but their roles and targets remain unclear.
• The phosphatase PP2A-B55α is crucial for mitotic exit and cytokinesis in mammals.

Purpose of the Study:

• To investigate the redundancy of Cdc14A and Cdc14B in DNA repair.
• To identify the DNA repair pathways involving Cdc14B.
• To elucidate the downstream targets of Cdc14B in DNA repair.

Main Methods:

• Generating and analyzing Cdc14B knockout mouse embryonic fibroblasts (MEFs).
• Assessing DNA double-strand break (DSB) repair after ionizing radiation (IR) exposure.
• Investigating homologous recombination (HR) and nonhomologous end joining (NHEJ) pathway efficiencies.
• Identifying downstream targets using molecular assays.

Main Results:

• Cdc14B knockout MEFs exhibited defects in repairing IR-induced DSBs, particularly at later passages when Cdc14A levels were reduced.
• Compromising both Cdc14A and Cdc14B levels led to repair defects even at early passages, confirming functional redundancy.
• Cdc14B deficiency impaired both major DSB repair pathways: HR and NHEJ.
• Cdh1 was identified as a downstream target of Cdc14B in the context of DSB repair.

Conclusions:

• Cdc14A and Cdc14B function redundantly in the repair of DNA double-strand breaks.
• Cdc14B plays a significant role in both homologous recombination and nonhomologous end joining pathways.
• Cdh1 is a novel downstream effector of Cdc14B-mediated DNA repair.