In vivo labelling of functional ribosomes reveals spatial regulation during starvation in Podospora anserina.

BACKGROUND

To date, in eukaryotes, ribosomal protein expression is known to be regulated at the transcriptional and/or translational levels. But other forms of regulation may be possible.

RESULTS

Here, we report the successful tagging of functional ribosomal particles with a S7-GFP chimaeric protein, making it possible to observe in vivo ribosome dynamics in the filamentous fungus Podospora anserina. Microscopic observations revealed a novel kind of ribosomal protein regulation during the passage between cell growth and stationary phases, with a transient accumulation of ribosomal proteins and/or ribosome subunits in the nucleus, possibly the nucleolus, being observed at the beginning of stationary phase.

CONCLUSION

Nuclear sequestration can be another level of ribosomal protein regulation in eukaryotic cells. This may contribute to the regulation of cell growth and division.