Nuclear pore links Fob1-dependent rDNA damage relocation to lifespan control.

Area of Science:

• Cell Biology
• Genetics
• Molecular Biology

Background:

• Replication fork blocking protein Fob1 in budding yeast causes DNA double-strand breaks at the ribosomal RNA gene (rDNA) locus.
• rDNA damage is linked to genomic instability, reduced replicative lifespan, and spatial relocation of breaks from the nucleolus to the nuclear periphery.
• The precise organization and functional significance of these spatial transitions in genome stability and aging remain poorly understood.

Purpose of the Study:

• To investigate the subnuclear localization of site-specific rDNA breaks.
• To elucidate the functional relationship between damaged rDNA and nuclear pores.
• To understand how spatial organization of rDNA damage influences genome stability and replicative lifespan.

Main Methods:

• Quantitative fluorescence microscopy was employed to analyze the subnuclear localization of damaged rDNA.
• Site-specific rDNA breaks were induced and tracked within budding yeast cells.
• Genetic manipulations, including deletion of Fob1 and disruption of nuclear pore association, were performed.

Main Results:

• Damaged rDNA was observed to accumulate at the nucleolar-nucleoplasmic interface, adjacent to the nuclear envelope.
• Cells lacking nuclear pore association exhibited significant rDNA instability, partially rescued by Fob1 deletion.
• Disruption of nuclear pore association shortened replicative lifespan, with partial rescue by Fob1 deletion, indicating both Fob1-dependent and independent pathways.

Conclusions:

• Nuclear pores play a role in spatially organizing Fob1-induced rDNA damage at the nuclear periphery.
• This spatial organization is critical for maintaining rDNA stability and extending replicative lifespan in budding yeast.
• Nuclear pores contribute to longevity through both Fob1-dependent and Fob1-independent mechanisms related to rDNA damage.