RNF126 Quenches RNF168 Function in the DNA Damage Response

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• DNA damage response (DDR) is critical for genome stability and preventing cancer.
• Ubiquitin modifications are key regulators of DDR signaling and DNA repair pathways.

Purpose of the Study:

• To investigate the role of E3 ligase RNF126 in the DNA damage response.
• To elucidate the mechanism by which RNF126 influences DDR and DNA repair.

Main Methods:

• Utilized UV laser micro-irradiation to induce DNA damage.
• Investigated protein-protein interactions and ubiquitination events using co-immunoprecipitation and Western blotting.
• Assessed DNA repair efficiency via homologous recombination assays and focus formation of DDR markers.

Main Results:

• RNF126 is recruited to sites of DNA damage in a RNF8-dependent manner.
• RNF126 directly interacts with and ubiquitinates E3 ligase RNF168.
• RNF126 overexpression inhibits H2AX ubiquitination and downstream focus formation of 53BP1 and RAP80.
• Both RNF126 overexpression and downregulation impair homologous recombination repair of DNA double-strand breaks.

Conclusions:

• RNF126 acts as a negative regulator of RNF168 activity within the DDR pathway.
• Maintaining appropriate cellular levels of RNF126 is essential for efficient homologous recombination-mediated repair of DNA double-strand breaks.