How RNA transcripts coordinate DNA recombination and repair.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• RNA transcripts are known to facilitate homology-directed DNA repair in yeast, a process dependent on the RAD52 protein.
• The precise molecular mechanisms underlying this RNA-DNA repair remain largely uncharacterized.

Purpose of the Study:

• To elucidate the molecular basis of RNA-DNA repair.
• To investigate the direct role of RAD52 protein in cooperating with RNA to facilitate DNA repair.

Main Methods:

• In vitro reconstitution assays were employed to study the interaction between RAD52 and RNA.
• Mechanisms of RNA-DNA repair were analyzed using biochemical approaches.

Main Results:

• RAD52 directly forms sequence-directed ribonucleoprotein complexes with RNA, promoting two distinct RNA-DNA repair pathways.
• A RNA-bridging mechanism involves RAD52 assembling RNA-DNA hybrids to facilitate DNA break repair.
• An RNA-templated mechanism utilizes RAD52-mediated RNA-DNA hybrids for reverse transcription-dependent sequence transfer, enabling DNA recombination.

Conclusions:

• RNA transcripts and RAD52 protein cooperate to coordinate homology-directed DNA repair and recombination, even without a DNA donor.
• Transcription of homologous DNA templates in trans enhances both identified RNA-DNA repair mechanisms.
• These findings reveal a direct role for transcription in the process of RNA-DNA repair.