The Rea1 Tadpole Loses Its Tail

More than 170 assembly factors aid the construction and maturation of yeast ribosomes. After these factors' functions are completed, they must be released from preribosomes. In this issue, Ulbrich et al. (2009) describe a mechanochemical process through which the AAA ATPase Rea1 induces release of an assembly protein complex from preribosomes

Assembly of Saccharomyces cerevisiae 60S ribosomal subunits: role of factors required for 27S pre‐rRNA processing

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102169/1/embj2011338-sup-0001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102169/2/embj2011338.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102169/3/embj2011338-sup-0002.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102169/4/embj2011338-reviewer_comments.pd

Saccharomyces cerevisiae ribosomal protein L26 is not essential for ribosome assembly and function

Ribosomal proteins play important roles in ribosome biogenesis and function. Here, we study the evolutionarily conserved L26 inSaccharomyces cerevisiae, which assembles into pre-60S ribosomal particles in the nucle(ol)us. Yeast L26 is one of the many ribosomal proteins encoded by two functional genes. We have disrupted both genes; surprisingly, the growth of the resulting rpl26null mutant is apparently identical to that of the isogenic wild-type strain. The absence of L26 minimally alters 60S ribosomal subunit biogenesis. Polysome analysis revealed the appearance of half-mers. Analysis of pre-rRNA processing indicated that L26 is mainly required to optimize 27S pre-rRNA maturation, without which the release of pre-60S particles from the nucle-(ol)us is partially impaired. Ribosomes lacking L26 exhibit differential reactivity to dimethylsulfate in domain I of 25S/5.8S rRNAs but apparently are able to support translationin vivowith wild-type accuracy. The bacterial homologue of yeast L26, L24, is a primary rRNA binding protein required for 50S ribosomal subunit assemblyin vitroandin vivo. Our results underscore potential differences between prokaryotic and eukaryotic ribosome assembly. We discuss the reasons why yeast L26 plays such an apparently nonessential role in the cel

Breaking the Mould: the Study Centre Approach

At an FE College in Worcester, the traditional library has been replaced by study centres with a significant increase in staff, in a move to focus on the learner. How did this radical change go down with the students, the staff and the teachers

Yeast Polypeptide Exit Tunnel Ribosomal Proteins L17, L35, and L37 are Necessary to Recruit Late-assembling Factors Required for 27SB Pre-rRNA Processing

Ribosome synthesis involves the coordinated folding and processing of pre-rRNAs with assembly of ribosomal proteins. In eukaryotes, these events are facilitated by trans-acting factors that propel ribosome maturation from the nucleolus to the cytoplasm. However, there is a gap in understanding how ribosomal proteins configure pre-ribosomes in vivo to enable processing to occur. Here, we have examined the role of adjacent yeast r-proteins L17, L35 and L37 in folding and processing of pre-rRNAs, and binding of other proteins within assembling ribosomes. These three essential ribosomal proteins, which surround the polypeptide exit tunnel, are required for 60S subunit formation as a consequence of their role in removal of the ITS2 spacer from 27SB pre-rRNA. L17-, L35- and L37-depleted cells exhibit turnover of aberrant pre-60S assembly intermediates. Although the structure of ITS2 does not appear to be grossly affected in their absence, these three ribosomal proteins are necessary for efficient recruitment of factors required for 27SB pre-rRNA processing, namely, Nsa2 and Nog2, which associate with pre-60S ribosomal particles containing 27SB pre-rRNAs. Altogether, these data support that L17, L35 and L37 are specifically required for a recruiting step immediately preceding removal of ITS2

Interregional Cooperation and Smart Specialisation: a Lagging Regions Perspective

This report has been prepared as part of the Lagging Regions project of the JRC. In the 2021-2027 programming period, smart specialisation strategies will be required to meet a series of fulfilment criteria around the relevant "enabling condition" of good governance. One such criterion relates to international collaboration, or measures for enhancing cooperation with partners in different countries in areas designated as priority areas for smart specialisation. The potential for Lagging Regions to participate in interregional and international cooperation remains under-exploited, and this report determines specific challenges as well as potential benefits and opportunities that are relevant for low-growth and low-income regions. An exploration of interregional and international cooperation aims to contribute to a better understanding of its role in strengthening innovation ecosystems and its interaction with Smart Specialisation in the context of Lagging Regions.JRC.B.3-Territorial Developmen

rRNA Maturation in Yeast Cells Depleted of Large Ribosomal Subunit Proteins

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

Cohesion policy after Brexit: the economic, social and institutional challenges

Since 1988, when the current EU Cohesion Policy was introduced, it has played an influential role in setting priorities for policies aimed at dealing with the effects of European economic integration on regional and social disparities. Although, latterly, the amount of money spent in the UK through the European Structural and Investment Funds (ESIF) has declined, EUprogrammes have had a disproportionate effect on the design and implementation of UK policies shaping regional and local economic and social development. This paper starts by recalling how EU Cohesion Policy has functioned in the UK, then considers how Brexit may affect regional and social development and the need for a corresponding policy response, focusing on the sorts of policies currently supported by the European Regional Development Fund (ERDF) and the European Social Fund (ESF). The paper shows that filling the policy vacuum will be far from straightforward because complementary national policies and institutional frameworks have lacked consistency or coherence. It concludes by examining the wider policy issues arising from rethinking domestic policy outside the ESIF framework.The sub-national level, in particular, will need a fresh approach following Brexit

Ebp2 and Brx1 function cooperatively in 60S ribosomal subunit assembly in Saccharomyces cerevisiae

The yeast protein Ebp2 is required for early steps in production of 60S ribosomal subunits. To search for cofactors with which Ebp2 functions, or substrates on which it acts, we screened for mutants that were synthetically lethal (sl) with the ebp2-14 mutation. Four different mutant alleles of the 60S ribosomal subunit assembly factor Brx1 were found. To investigate defects of the double mutant, we constructed strains conditional for the ebp2-14 brx1- synthetic lethal phenotype. These ebp2-14 brx1 mutants were defective in processing of 27S pre-rRNA and production of 60S subunits, under conditions where each single mutant was not. Ebp2 and Brx1 exhibit a strong two-hybrid interaction, which is eliminated by some combinations of brx1 and ebp2 mutations. In one such mutant, Ebp2 and Brx1 can still associate with pre-ribosomes, but subunit maturation is perturbed. Depletion of either Ebp2 or Brx1 revealed that Brx1 requires Ebp2 for its stable association with pre-ribosomes, but Ebp2 does not depend on the presence of Brx1 to enter pre-ribosomes. These results suggest that assembly of 60S ribosomal subunits requires cooperation of Ebp2 with Brx1, together with other molecules present in pre-ribosomes, potentially including several found in assembly subcomplexes with Brx1 and Ebp2