Abstract

In the final steps of yeast ribosome synthesis, immature translation-incompetent pre-40S particles that contain 20S pre-rRNA are converted to the mature translation-competent subunits containing the 18S rRNA. An assay for 20S pre-rRNA cleavage in purified pre-40S particles showed that cleavage by the PIN domain endonuclease Nob1 was strongly stimulated by the GTPase activity of Fun12, the yeast homolog of cytoplasmic translation initiation factor eIF5b. Cleavage of the 20S pre-rRNA was also inhibited in vivo and in vitro by blocking binding of Fun12 to the 25S rRNA through specific methylation of its binding site. Cleavage competent pre-40S particles stably associated with Fun12 and formed 80S complexes with 60S ribosomal subunits. We propose that recruitment of 60S subunits promotes GTP hydrolysis by Fun12, leading to structural rearrangements within the pre-40S particle that bring Nob1 and the pre-rRNA cleavage site together.

Links

Publisher Full Text

Authors

Lebaron S, Schneider C, van Nues RW, Swiatkowska A, Walsh D, Böttcher B, Granneman S, Watkins NJ, Tollervey D

Institution

Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Edinburgh, Scotland, UK.

Source

Nature structural & molecular biology 19:8 2012 Aug pg 744-53

MeSH

Adenosine Triphosphate
Base Sequence
Binding Sites
Eukaryotic Initiation Factor-2
Guanosine Triphosphate
Models, Molecular
Molecular Sequence Data
Nuclear Proteins
Nucleic Acid Conformation
Protein Conformation
RNA Precursors
RNA Processing, Post-Transcriptional
RNA, Fungal
RNA, Ribosomal
Ribosome Subunits, Large, Eukaryotic
Ribosome Subunits, Small, Eukaryotic
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22751017