Pre-ribosomes on the road from the nucleolus to the cytoplasm.
Eukaryotic ribosomes are assembled in the nucleolus before export to the cytoplasm. Ribosome formation is a highly dynamic and coordinated multistep process, which requires synthesis, processing and modification of pre-rRNAs, assembly with ribosomal proteins and transient interaction of numerous non-ribosomal factors with the evolving pre-ribosomal particles. In the past two years, exciting insights into the sequential events occurring during pre-ribosome formation have been obtained, thanks largely to the advances in proteomic analyses. We now have a first biochemical map of the earliest 90S pre-ribosomes and of their daughter pre-40S and pre-60S ribosomal subunits along their path from the nucleolus to the cytoplasm. The future challenge will be to assign functions to the more than 150 non-ribosomal factors that transiently associate with the developing pre-ribosomes.
Biochemie-Zentrum Heidelberg (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany. h.tschochner@uni-hd.de
Herbert
H
Tschochner
Ed
E
Hurt
D021581:Active Transport, Cell Nucleus; D002466:Cell Nucleolus / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D008954:Models, Biological; D016366:Open Reading Frames; D020543:Proteome; D012322:RNA Precursors / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D020718:Ribonucleoproteins, Small Nucleolar; D012269:Ribosomal Proteins / Q000502:physiology*; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*
D020543:Proteome; D012322:RNA Precursors; D012335:RNA, Ribosomal; D020718:Ribonucleoproteins, Small Nucleolar; D012269:Ribosomal Proteins