Znf598-mediated Rps10/eS10 Ubiquitination contributes to the ribosome ubiquitination dynamics during zebrafish development

The ribosome is a translational apparatus that comprises about 80 ribosomal proteins and four rRNAs. Recent studies reported that ubiquitination of the ribosomal proteins plays a pivotal role in translational control and ribosome-associated quality control (RQC). However, little is known about the dynamics of ribosome ubiquitination under complex biological processes of multicellular organisms. To study ribosome ubiquitination during animal development, we generated a zebrafish strain that expresses a FLAG-tagged ribosomal protein Rpl36/eL36 from its endogenous locus. Combining affinity purification of ribosomes from rpl36-FLAG zebrafish embryos with immunoblotting analysis, we analyzed ribosome ubiquitination during zebrafish development. Our data showed that ubiquitination of ribosomal proteins dynamically changed as development proceeded. We further revealed that Znf598, an E3 ubiquitin ligase that triggers RQC, contributed to the ribosome ubiquitination during zebrafish development. LC-MS/MS analysis and immunoblotting analysis identified lysines 139 of ribosomal protein Rps10/eS10 as pivotal ubiquitination sites on the ribosome during development. Finally, we demonstrated that an Rps10 K139/140R mutation reduced overall ribosome ubiquitination pattern. Collectively, these results reveal dynamics and complexity of ribosome ubiquitination in zebrafish development.