Molecular mechanisms of eukaryotic ribosome biogenesis

Lead Research Organisation: MRC Laboratory of Molecular Biology

Abstract

Human leukaemias are a significant cause of morbidity and mortality in children and adults. However, we have little understanding of the molecular basis of the multistep progression to leukaemia. A major goal of our studies is to identify and characterise the function of new molecules that participate in the development of these cancers of the blood. We further aim to determine the three-dimensional shape of the molecules involved in order to facilitate the development of novel targeted approaches to therapy.

Technical Summary

Ribosome assembly is an essential, highly conserved process that is tightly coupled to cell growth and proliferation. However, the molecular mechanisms underlying this process remain poorly understood. Excitingly, a new class of cancer predisposition syndromes collectively called the “ribosomopathies” has recently emerged that harbour mutations in components of the ribosome assembly pathway. In particular, we have discovered that the SBDS protein that is deficient in the leukaemia predisposition disorder Shwachman-Diamond syndrome is required for maturation of the large ribosomal subunit. SBDS controls the translational activation of ribosomes by catalysing dissociation of the anti-association factor eIF6 from nascent 60S subunits, but the precise mechanism remains unclear. We propose a model in which GTP-dependent conformational change in elongation factor-like 1 (EFL1) triggers an inter-domain rotation in SBDS that directly or indirectly triggers eIF6 release. We aim to test this hypothesis at the molecular level by combining the latest advances in single-particle cryo-electron microscopy and NMR spectroscopy with X-ray crystallography, biochemistry and innovative genetic platforms. We will test the hypothesis that eIF6 release is a prerequisite for eviction of additional assembly factors whose specific role in ribosome assembly we will determine. Finally, we will apply state-of-the-art genetic approaches to identify additional components of the pathway. Novel insights into the mechanisms of ribosome assembly are exploitable not only for the design of targeted therapeutics for the ribosomopathies, but also for cancer drug discovery more generally.
To facilitate translation of this work to direct clinical care, we have initiated collaborations with paediatric haematologists in the UK and in Europe. We will participate in tissue banking to facilitate prospective studies through the Haematology Department at Addenbrookes Hospital in accordance with National and Local ethical guidelines.

Publications

10 25 50
 
Description AICR Project Grant
Amount £162,000 (GBP)
Organisation Association for International Cancer Research 
Sector Charity/Non Profit
Country United Kingdom
Start 04/2008 
End 03/2011
 
Description Leukaemia Society of America
Amount £75,000 (GBP)
Organisation The Leukemia & Lymphoma Society 
Sector Charity/Non Profit
Country United States
Start 03/2006 
End 03/2011
 
Description Tesni Parry Memorial Fund
Amount £100,000 (GBP)
Organisation University of Cambridge 
Sector Academic/University
Country United Kingdom
Start 04/2011 
End 03/2013
 
Description Characterization of RNA aptamers to AML1 
Organisation University of Leeds
Country United Kingdom 
Sector Academic/University 
PI Contribution Purification of protein complexes
Impact Barton JL, Bunka DH, Knowling SE, Lefevre P, Warren AJ, Bonifer C, Stockley PG. Characterization of RNA aptamers that disrupt the RUNX1-CBFbeta/DNA complex. Nucleic Acids Res. (2009) 37:6818-30. Epub 2009 Sep 9.
 
Description Charles Boone, University of Toronto 
Organisation University of Toronto
Country Canada 
Sector Academic/University 
PI Contribution Together with the Boone Laboratory, we identified the function of the yeast homologue of the SBDS gene mutated in Shwachman-Diamond syndrome using biochemical and genetic approaches in yeast
Collaborator Contribution Publication PubMed ID: 17353896
Impact Publication PubMed ID: 17353896
 
Description Invited talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact American Society of Hematology, Orlando, Florida Mixed international audience of scientists and professional Haematologists

Publication of research findings in the journal Nature Genetics 2007. Subsequent productive collaborations and interactions with other investigators in the field, successful Programme funding application to the Leukaemia Research Fund
Year(s) Of Engagement Activity 2006