EMBL researchers visualise human ribosome assembly pathways

Researchers at EMBL Heidelberg have successfully visualised the human nucleolus, the cellular site responsible for ribosome production, using a combination of cryo-electron tomography (cryo-ET) and correlative light and electron microscopy (CLEM).

The study provided the first in-cell structural snapshots of two key ribosomal subunit precursors: the SSU processome and the pre-60S. These findings revealed new assembly configurations and challenged existing models. Specifically, the team discovered that a protein factor previously believed to bind late in the assembly process actually binds much earlier. Additionally, the research showed that ribosomes do not mature through a linear assembly line moving from the centre of the nucleolus to its edge.