A single subunit, Dis3, is essentially responsible for yeast exosome core activity

Area of Science:

• Molecular Biology
• Biochemistry
• Cell Biology

Background:

• The exosome is a major eukaryotic 3' --> 5' exonuclease complex.
• Its conserved core comprises nine subunits forming a ring structure.
• Previous research suggested all core subunits possess exoRNase activity.

Purpose of the Study:

• To identify the catalytic subunit responsible for exosome core activity.
• To investigate the roles of Dis3 and Rrp41 in exosome function.
• To elucidate the essential function of the exosome ring.

Main Methods:

• Purification and biochemical characterization of the exosome core complex.
• In vitro enzymatic assays using wild-type and mutant Dis3.
• In vivo analysis of Dis3 and Rrp41 mutants in yeast.

Main Results:

• Dis3 is the primary catalytic subunit responsible for exosome core hydrolytic activity.
• A catalytically inactive Dis3 mutant phenocopies exosome depletion.
• Mutations in Rrp41 did not significantly alter yeast exosome function.
• The exosome ring facilitates interactions with protein partners.

Conclusions:

• Dis3 is the essential enzyme driving exosome-mediated RNA degradation.
• The exosome ring's structure is crucial for protein interactions and essential function.
• This study clarifies the subunit responsible for the exosome's core exonuclease activity.