DNA damage response and spindle assembly checkpoint function throughout the cell cycle to ensure genomic integrity

Area of Science:

• Cell Biology
• Genetics
• Molecular Biology

Background:

• Cell cycle progression relies on accurate DNA replication and chromosome segregation.
• The DNA damage response (DDR) and spindle assembly checkpoint (SAC) are critical pathways preventing genome instability.
• These pathways monitor DNA integrity and proper spindle attachment, respectively, to delay cell division for repairs.

Purpose of the Study:

• To investigate the collaborative function of the DDR and SAC in ensuring genome integrity.
• To elucidate the roles of DDR and SAC components beyond their canonical functions.
• To determine if the observed interactions are conserved across species.

Main Methods:

• Utilized C. elegans germ cells as a model system.
• Observed the enrichment of SAC and DDR components on chromatin following metaphase defects.
• Assessed the requirement of SAC and DDR for metaphase delays and DNA repair.
• Investigated the role of MAD1, MAD2, CENPA, ATR, and CHK1 in response to DNA damage and replication stress.
• Examined MAD1/MAD2 relocalization in human cells under replication perturbations.

Main Results:

• DDR and SAC function synergistically throughout the cell cycle in C. elegans germ cells.
• Both pathways are essential for metaphase delays, and SAC has roles beyond CDC20 interaction.
• DDR-dependent enrichment of MAD2 and CENPA at the nuclear periphery occurs in response to DNA damage.
• SAC and CENPA are required for efficient DNA repair, suggesting a role in mediating repair via nuclear periphery interactions.
• Replication stress induces MAD1/MAD2 relocalization in human cells, indicating conserved functions.

Conclusions:

• The DDR and SAC pathways cooperate to maintain genome integrity, with SAC playing a role in DNA repair.
• The interaction between SAC components and the nuclear periphery, mediated by CENPA, is crucial for DNA repair.
• The findings highlight a conserved mechanism for genome maintenance involving the spindle assembly checkpoint and DNA damage response.