An aminoacylation-dependent nuclear tRNA export pathway in yeast

Area of Science:

• Molecular Biology
• Cell Biology

Background:

• Yeast Los1p is crucial for nuclear export of transfer RNA (tRNA).
• However, the export of some intronless tRNAs is not affected by LOS1 disruption, suggesting other factors are involved.

Purpose of the Study:

• To identify additional factors involved in tRNA nuclear export.
• To investigate the roles of tRNA aminoacylation and translation elongation factor eEF-1A in this process.

Main Methods:

• Performed a suppressor screen of a synthetically lethal los1 mutant.
• Utilized fluorescence in situ hybridization to track tRNA localization.
• Investigated tRNA export under conditions of inhibited aminoacylation.

Main Results:

• Identified the essential translation elongation factor eEF-1A as a key factor in tRNA export.
• Disruption of eEF-1A impaired nuclear export of all tested tRNA species (spliced and intronless).
• Inhibition of tRNA aminoacylation exacerbated tRNA nuclear export defects, leading to nucleolar accumulation.

Conclusions:

• Both tRNA aminoacylation and eEF-1A are essential for efficient nuclear tRNA export in yeast.
• These findings suggest a coordinated mechanism between protein translation and nuclear tRNA processing/transport machinery.