Identification of a DNA Damage-Induced Alternative Splicing Pathway That Regulates p53 and Cellular Senescence...

Area of Science:

• Molecular Biology
• Genetics
• Cancer Research

Background:

• Cellular responses to DNA damage are crucial for preventing cancer and aging.
• The DNA-damage response (DDR) pathway's role in regulating gene expression and cellular fate is complex.
• Alternative splicing is increasingly recognized as a key modulator of cellular processes.

Purpose of the Study:

• To identify and characterize a novel DDR pathway that controls alternative splicing.
• To investigate the pathway's role in DNA damage-induced cellular senescence.
• To elucidate the molecular mechanisms linking DNA damage, splicing, and senescence.

Main Methods:

• Ionizing radiation (IR) treatment to induce DNA damage.
• CRISPR/Cas9 gene editing to selectively knockout p53β.
• Western blotting and RT-PCR to assess protein and RNA levels.
• Analysis of splicing factor recruitment and activity.

Main Results:

• Ionizing radiation inhibits SMG1 activity, altering p53 pre-mRNA splicing.
• RPL26 and SRSF7 are recruited to p53 pre-mRNA, promoting the generation of p53β.
• Disruption of this pathway reduces senescence markers and impairs the repression of senescence regulators.
• Cells lacking p53β fail to repress negative regulators of cellular senescence and aging.

Conclusions:

• A new DDR pathway regulating alternative splicing, including TP53, has been identified.
• This pathway is critical for DNA damage-induced cellular senescence.
• Modulation of this pathway impacts cellular aging and cancer pathogenesis.