NUCKS1 is a novel RAD51AP1 paralog important for homologous recombination and genome stability

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• NUCKS1 (nuclear casein kinase and cyclin-dependent kinase substrate 1) is a vertebrate-specific protein with limited known function.
• NUCKS1 shows sequence homology to RAD51AP1, suggesting they are paralogs.

Purpose of the Study:

• To investigate the function of NUCKS1 in DNA repair and genome stability.
• To compare NUCKS1 function with that of RAD51AP1.

Main Methods:

• Depletion of NUCKS1 in human cells using knockdown techniques.
• Assessing DNA repair by homologous recombination (HR) capacity.
• Evaluating cellular sensitivity to mitomycin C (MMC).
• Analyzing DNA replication fork progression and origin utilization.

Main Results:

• NUCKS1 depletion impairs homologous recombination (HR) and chromosome stability.
• NUCKS1-depleted cells exhibit increased sensitivity to mitomycin C (MMC) and chromatid breaks.
• Loss of NUCKS1 slows DNA replication fork progression and increases new origin utilization.
• Recombinant NUCKS1 binds DNA with lower affinity than RAD51AP1 but shares DNA binding preference.

Conclusions:

• NUCKS1 is a chromatin-associated protein vital for the DNA damage response and homologous recombination (HR).
• NUCKS1 plays a critical role in maintaining genome integrity and functions in HR, a key tumor suppressor pathway.