Senataxin resolves RNA:DNA hybrids forming at DNA double-strand breaks to prevent translocations

Area of Science:

• Molecular Biology
• Genetics
• Neuroscience

Background:

• Ataxia with oculomotor apraxia 2 (AOA-2) and amyotrophic lateral sclerosis 4 (ALS4) are linked to mutations in the senataxin (SETX) gene.
• Senataxin is a putative RNA:DNA helicase crucial for transcription and genome integrity.

Purpose of the Study:

• To investigate the role of senataxin at DNA double-strand breaks (DSBs) within transcriptionally active genes.
• To elucidate the mechanism by which senataxin influences DSB repair and cellular viability.

Main Methods:

• Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) to map senataxin binding sites.
• Genome-wide analysis of RNA:DNA hybrids and DNA repair protein recruitment at DSBs.

Main Results:

• Senataxin is recruited to DSBs in transcriptionally active loci.
• RNA:DNA hybrids accumulate near DSBs, with depletion at senataxin binding sites.
• Senataxin promotes Rad51 recruitment, limits illegitimate DNA end rejoining, and enhances cell viability after DSBs in active genes.

Conclusions:

• Senataxin plays a critical role in managing DSBs within active genes to prevent translocations and maintain genomic stability.
• Understanding senataxin's function provides novel insights into the molecular basis of AOA-2 and ALS4 neuropathies.