BARD1 recognizes pre-rRNA for DNA damage repair and rRNA biogenesis

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• The BRCA1/BARD1 complex is known to be involved in DNA repair pathways.
• The precise roles and mechanisms of the BRCA1/BARD1 complex in pre-ribosomal RNA (pre-rRNA) recognition and its downstream effects remain unclear.

Purpose of the Study:

• To elucidate the molecular mechanisms by which the BARD1 protein interacts with pre-rRNA.
• To investigate the functional consequences of BARD1-pre-rRNA binding disruption on DNA repair and cellular processes.

Main Methods:

• Identification and characterization of a conserved pre-rRNA binding site in BARD1.
• Site-directed mutagenesis to disrupt BARD1-pre-rRNA binding.
• Assessment of homologous recombination (HR) repair efficiency.
• Analysis of BARD1 localization within the nucleolus.
• Quantification of rRNA biogenesis and protein synthesis levels.

Main Results:

• A highly conserved pre-rRNA binding site on BARD1 was identified.
• Mutation of this site abolished pre-rRNA binding and significantly impaired homologous recombination (HR) repair.
• BARD1 was found to localize in the nucleolus and regulate rRNA biogenesis.
• Loss of BARD1 function led to decreased pre-rRNA levels and reduced protein synthesis.

Conclusions:

• BARD1 plays a critical role in coordinating pre-rRNA binding with double-strand break (DSB) repair.
• BARD1 is essential for nucleolar function, regulating rRNA biogenesis and consequently impacting overall protein synthesis.
• This study reveals a novel dual function of BARD1 in both DNA repair and protein synthesis pathways.