RAD52 and ERCC6L/PICH have a compensatory relationship for genome stability in mitosis

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• RAD52 is a DNA repair protein with strand annealing and recombination mediator roles.
• RAD52 is crucial for genome stability in both interphase and mitotic cells.
• RAD52 is not essential for cell viability, prompting investigation into its synthetic lethal interactions.

Purpose of the Study:

• To identify genes synthetically lethal with RAD52.
• To investigate the functional relationship between RAD52 and ERCC6L in maintaining genome stability.
• To understand the roles of RAD52 and ERCC6L in mitigating DNA damage during mitosis.

Main Methods:

• Genome-wide CRISPR knock-out screens were employed to identify synthetic lethal interactions with RAD52.
• Secondary screening assessed gene depletion effects on viability and genome instability (53BP1 foci) in RAD52-deficient cells.
• Functional assays examined RAD52 and ERCC6L interplay under normal conditions, replication stress, and topoisomerase IIα inhibition.

Main Results:

• Hundreds of candidate synthetic lethal interactions with RAD52 were identified.
• ERCC6L was identified as a key factor whose depletion exacerbates genome instability in RAD52-deficient cells.
• RAD52 deficiency increased ERCC6L-marked anaphase bridges, while ERCC6L depletion elevated RAD52 foci, particularly under replication stress.

Conclusions:

• RAD52 and ERCC6L function in a compensatory manner to maintain genome stability during mitosis.
• The interplay between RAD52 and ERCC6L is critical for resolving DNA damage and ensuring genomic integrity, especially under stress conditions.