PT  - JOURNAL ARTICLE
AU  - Sheu-Gruttadauria, Jessica
AU  - Yan, Xiaowei
AU  - Stuurman, Nico
AU  - Floor, Stephen N.
AU  - Vale, Ronald D.
TI  - Nucleolar dynamics are determined by the ordered assembly of the ribosome
AID  - 10.1101/2023.09.26.559432
DP  - 2023 Jan 01
TA  - bioRxiv
PG  - 2023.09.26.559432
4099  - http://biorxiv.org/content/early/2023/09/27/2023.09.26.559432.short
4100  - http://biorxiv.org/content/early/2023/09/27/2023.09.26.559432.full
AB  - Ribosome biogenesis is coordinated within the nucleolus, a biomolecular condensate that exhibits dynamic material properties that are thought to be important for nucleolar function. However, the relationship between ribosome assembly and nucleolar dynamics is not clear. Here, we screened 364 genes involved in ribosome biogenesis and RNA metabolism for their impact on dynamics of the nucleolus, as measured by automated, high-throughput fluorescence recovery after photobleaching (FRAP) of the nucleolar scaffold protein NPM1. This screen revealed that gene knockdowns that caused accumulation of early rRNA intermediates were associated with nucleolar rigidification, while accumulation of late intermediates led to increased fluidity. These shifts in dynamics were accompanied by distinct changes in nucleolar morphology. We also found that genes involved in mRNA processing impact nucleolar dynamics, revealing connections between ribosome biogenesis and other RNA processing pathways. Together, this work defines mechanistic ties between ribosome assembly and the biophysical features of the nucleolus, while establishing a toolbox for understanding how molecular dynamics impact function across other biomolecular condensates.Competing Interest StatementThe authors have declared no competing interest.