Final Report Summary - EURIBIO (Dissecting the biogenesis of eukaryotic ribosomal subunits)
Eukaryotic ribosome assembly a spectacular example of a highly dynamic regulated process that stretches through different cellular territories: the nucleus, nucleoplasm and the cytoplasm. This poorly understood process, which begins in the nucleolus, requires >350 conserved transiently associating assembly factors. Knowledge regarding the precise site(s) of action of these factors and their function on pre-ribosomes remains rudimentary. Upon accomplishing their task(s), early acting assembly factors are shed in the nucleoplasm preparing pre-ribosomes for nuclear export. Export competent pre-ribosomes are independently transported through nuclear pore complexes into the cytoplasm where they undergo maturation before initiating translation. These final steps involve the release of assembly and transport factors that travel with pre-ribosomal particles into the cytoplasm. These steps are highly regulated; permitting only correctly assembled pre-ribosomal particles complete maturation to translation competent ribosomes.
By employing diverse approaches in budding yeast, in combination with quantitative proteomic and integrative structural biology approaches, our research has revealed three different aspects of eukaryotic ribosome assembly:
(1) The uncharted interface between nucleo-cytoplasmic transport machinery and the ribosome assembly pathway.
(2) Compositional dynamics of pre-ribosomal particles as they travel from the nucleolus to the cytoplasm.
(3) Quality control steps that prevent incorrectly assembled pre-ribosomes from initiating translation.
Our analyses generated principles by which large complexes are assembled/disassembled, checked and targeted in vivo.
By employing diverse approaches in budding yeast, in combination with quantitative proteomic and integrative structural biology approaches, our research has revealed three different aspects of eukaryotic ribosome assembly:
(1) The uncharted interface between nucleo-cytoplasmic transport machinery and the ribosome assembly pathway.
(2) Compositional dynamics of pre-ribosomal particles as they travel from the nucleolus to the cytoplasm.
(3) Quality control steps that prevent incorrectly assembled pre-ribosomes from initiating translation.
Our analyses generated principles by which large complexes are assembled/disassembled, checked and targeted in vivo.