10.1184/R1/6104228.v1 Gisela Pöll Gisela Pöll Tobias Braun Tobias Braun Jelena Jakovljevic Jelena Jakovljevic Andreas Neueder Andreas Neueder Steffen Jakob Steffen Jakob John Woolford John Woolford Herbert Tschochner Herbert Tschochner Philipp Milkereit Philipp Milkereit rRNA maturation in yeast cells depleted of large ribosomal subunit proteins. Carnegie Mellon University 2009 Blotting Northern Cytoplasm Endonucleases Models Molecular Mutation RNA 3' End Processing RNA Precursors RNA Transport RNA Ribosomal 5.8S Ribosome Subunits Large Saccharomyces cerevisiae Saccharomyces cerevisiae Proteins 2009-01-01 00:00:00 Journal contribution https://kilthub.cmu.edu/articles/journal_contribution/rRNA_maturation_in_yeast_cells_depleted_of_large_ribosomal_subunit_proteins_/6104228 <p>The structural constituents of the large eukaryotic ribosomal subunit are 3 ribosomal RNAs, namely the 25S, 5.8S and 5S rRNA and about 46 ribosomal proteins (r-proteins). They assemble and mature in a highly dynamic process that involves more than 150 proteins and 70 small RNAs. Ribosome biogenesis starts in the nucleolus, continues in the nucleoplasm and is completed after nucleo-cytoplasmic translocation of the subunits in the cytoplasm. In this work we created 26 yeast strains, each of which conditionally expresses one of the large ribosomal subunit (LSU) proteins. In vivo depletion of the analysed LSU r-proteins was lethal and led to destabilisation and degradation of the LSU and/or its precursors. Detailed steady state and metabolic pulse labelling analyses of rRNA precursors in these mutant strains showed that LSU r-proteins can be grouped according to their requirement for efficient progression of different steps of large ribosomal subunit maturation. Comparative analyses of the observed phenotypes and the nature of r-protein-rRNA interactions as predicted by current atomic LSU structure models led us to discuss working hypotheses on i) how individual r-proteins control the productive processing of the major 5' end of 5.8S rRNA precursors by exonucleases Rat1p and Xrn1p, and ii) the nature of structural characteristics of nascent LSUs that are required for cytoplasmic accumulation of nascent subunits but are nonessential for most of the nuclear LSU pre-rRNA processing events.</p>