RNF4 prevents genomic instability caused by chronic DNA under-replication

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Eukaryotic genome stability relies on intricate molecular processes, including DNA repair and replication.
• Small ubiquitin-like modifier (SUMO)-targeted E3 ligases (STUbLs) are key enzymes in maintaining genome integrity.
• Previous studies identified a role for yeast STUbL Slx5/8 in preventing G2/M arrest under replication stress.

Purpose of the Study:

• To investigate the role of the human STUbL, RING finger protein 4 (RNF4), in MCM10 mutant cancer cells.
• To understand the functional relationship between RNF4 and MCM10 in regulating DNA replication and genome stability.
• To determine if RNF4 is required for origin activation during chronic replication stress in human cells.

Main Methods:

• Utilized human cancer cell lines with MCM10 mutations.
• Examined the genetic interaction between RNF4 and MCM10.
• Assessed DNA synthesis, origin firing, and cell cycle progression.
• Investigated DNA copy number alterations and cell viability.

Main Results:

• MCM10 and RNF4 independently promote origin firing but act epistatically in regulating DNA synthesis.
• The genetic interaction between RNF4 and MCM10 deficiency leads to G1-phase cell cycle arrest.
• RNF4 prevents severe DNA under-replication and copy number alterations in MCM10-deficient cells, preserving viability.
• Human RNF4 is essential for origin activation under chronic replication stress.

Conclusions:

• STUbLs employ species-specific mechanisms to maintain genome stability.
• Human RNF4 plays a critical role in origin activation during replication stress.
• RNF4 is vital for preventing DNA damage and maintaining viability in MCM10-compromised cancer cells.