Mouse Eri1 interacts with the ribosome and catalyzes 5.8S rRNA processing

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Eri1 is a conserved 3'-to-5' exoribonuclease found in organisms from yeast to humans.
• Ribosomes and ribosomal RNA (rRNA) are fundamental components of the protein synthesis machinery.

Purpose of the Study:

• To investigate the role of Eri1 in ribosomal RNA processing.
• To elucidate the mechanism by which Eri1 interacts with rRNA and its functional consequences.

Main Methods:

• Analysis of ribosomes from Eri1-deficient mice.
• In vitro and in-cell assays using Eri1 and its mutants.
• Subcellular localization studies of Eri1 in human and murine cells.
• Identification of RNA-binding residues in Eri1 domains.

Main Results:

• Eri1 associates with ribosomes and ribosomal RNA (rRNA).
• Eri1-deficient ribosomes exhibit aberrant 3' end extensions on 5.8S rRNA.
• Eri1, but not an inactive mutant, corrects abnormal 5.8S rRNA.
• Eri1 localizes to the cytoplasm, nucleus, and nucleolus, the site of rRNA synthesis.
• RNA-binding domains of Eri1 are crucial for its association with rRNA and 5.8S rRNA processing.

Conclusions:

• Eri1 catalyzes the final trimming step in 5.8S rRNA processing.
• Eri1 functionally and spatially connects RNA interference regulation with the translation machinery.