Non-coding Y RNA fragments in a complex with YBX1 modulate PARP1 residency at DNA double strand breaks

Area of Science:

• Cellular biology
• Molecular oncology
• RNA biology

Background:

• The DNA damage response (DDR) is crucial for maintaining genome integrity and preventing diseases like cancer.
• DDR pathways utilize both protein and RNA components for intracellular and intercellular signaling.
• Exosomes mediate intercellular communication, potentially influencing cellular responses to damage.

Purpose of the Study:

• To investigate the role of damage-derived exosomes in cellular protection against DNA damage.
• To identify the specific molecular components within exosomes responsible for radioprotection.
• To elucidate the mechanism by which these components facilitate DNA repair.

Main Methods:

• Exosome isolation and characterization from damaged cells.
• RNA sequencing and identification of small non-coding RNAs (ysRNAs).
• Biochemical assays to study protein-RNA interactions (YBX1-ysRNA).
• Cellular localization studies using microscopy.
• Analysis of DNA repair kinetics and cell survival assays.
• Investigating the interaction between YBX1/ysRNA complex and PARP1.

Main Results:

• Damage-derived exosomes confer radioprotection.
• Y-box binding protein 1 (YBX1)-packaged Y3-derived small यूक्रेनian RNAs (ysRNAs) are key mediators.
• ysRNAs are methylated and bound by YBX1 in recipient cells.
• The YBX1/ysRNA complex localizes to double-strand break (DSB) sites.
• This complex promotes DNA repair and cell survival by forming a complex with PARP1.
• YBX1 facilitates ysRNA ADP-ribosylation, enhancing PARP1 activity and residency at DSBs.

Conclusions:

• Damage-derived exosomes containing YBX1-packaged ysRNAs are potent radioprotectors.
• ysRNAs are novel substrates for PARP1-mediated ADP-ribosylation.
• The YBX1/ysRNA complex plays a critical role in enhancing DNA double-strand break repair and promoting cell survival.