RNA-mediated double-strand break repair by end-joining mechanisms

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• DNA double-strand breaks (DSBs) are critical DNA lesions requiring efficient repair for genomic integrity.
• Cells utilize multiple DSB repair pathways, including non-homologous end joining (NHEJ), homologous recombination (HR), and microhomology-mediated end joining (MMEJ).
• The direct role of RNA in modulating DSB repair outcomes, particularly via end-joining mechanisms, remains largely unexplored.

Purpose of the Study:

• To investigate the direct impact of transcript RNAs on DNA double-strand break repair outcomes.
• To determine if RNA influences DSB repair through non-homologous end joining (NHEJ) and microhomology-mediated end joining (MMEJ) pathways.
• To explore the sequence-specific nature of RNA-mediated modulation of DSB repair.

Main Methods:

• Experimental induction of DSBs or double-strand gaps in wild-type human and yeast cells.
• Analysis of DSB repair outcomes in the presence of various sense and antisense-transcript RNAs.
• Assessment of sequence complementarity between transcript RNAs and the broken DNA ends.

Main Results:

• Both sense and antisense-transcript RNAs were shown to influence DSB repair in a sequence-specific manner.
• Transcript RNAs promoted the repair of DSBs and double-strand gaps via NHEJ or MMEJ, independent of DNA synthesis.
• The observed RNA effects were dependent on sequence complementarity between the RNA and the DNA break site.

Conclusions:

• Transcript RNAs play a direct role in directing the repair of DNA double-strand breaks.
• RNA can modulate genome stability by influencing the choice and efficiency of DSB repair pathways.
• These findings suggest a novel mechanism by which RNA contributes to genome evolution.