Nuclear export competence of pre-40S subunits in fission yeast requires the ribosomal protein Rps2

• Published in: Nucleic acids research Vol. 36; no. 19; pp. 6132 - 6142
• Main Authors: Perreault, Audrey, Bellemer, Clément, Bachand, Francois
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-11-2008; Oxford Publishing Limited (England)
• Subjects: Active Transport, Cell Nucleus; Cell Nucleolus - metabolism; Cell Nucleus - metabolism; Gene Deletion; Genes, Essential; Molecular Biology; Ribosomal Proteins - genetics; Ribosomal Proteins - physiology; Ribosome Subunits, Small, Eukaryotic - metabolism; RNA Precursors - metabolism; RNA Processing, Post-Transcriptional; RNA, Ribosomal, 18S - biosynthesis; RNA-Binding Proteins - genetics; RNA-Binding Proteins - physiology; Saccharomyces cerevisiae; Schizosaccharomyces - genetics; Schizosaccharomyces - metabolism; Schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins - genetics; Schizosaccharomyces pombe Proteins - physiology
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkn625

Ribosome biogenesis is an evolutionarily conserved pathway that requires ribosomal and nonribosomal proteins. Here, we investigated the role of the ribosomal protein S2 (Rps2) in fission yeast ribosome synthesis. As for many budding yeast ribosomal proteins, Rps2 was essential for cell viability in fission yeast and the genetic depletion of Rps2 caused a complete inhibition of 40S ribosomal subunit production. The pattern of pre-rRNA processing upon depletion of Rps2 revealed a reduction of 27SA2 pre-rRNAs and the concomitant production of 21S rRNA precursors, consistent with a role for Rps2 in efficient cleavage at site A2 within the 32S pre-rRNA. Importantly, kinetics of pre-rRNA accumulation as determined by rRNA pulse-chases assays indicated that a small fraction of 35S precursors matured into 20S-containing particles, suggesting that most 40S precursors were rapidly degraded in the absence of Rps2. Analysis of steady-state RNA levels revealed that some pre-40S particles were produced in Rps2-depleted cells, but that these precursors were retained in the nucleolus. Our findings suggest a role for Rps2 in a mechanism that monitors pre-40S export competence.