RiboBright reveals cell-type-specific differences in ribosome organization and movement.

Ribosomes are responsible for protein synthesis in all living systems. Determining their cellular organization, movement, and translational activity is crucial for dissecting ribosomes' complex functions. In this study, we describe the development of a selective fluorescent probe for eukaryotic ribosomes - RiboBright. Using C-H activation, the natural product cycloheximide was aminated at the C13-position and fluorescently modified to afford RiboBright. We employ RiboBright for the quantification of ribosome content in 10 cell lines through microscopy and flow cytometry. RiboBright is applicable in live cells for tracking and quantification of ribosome movement and in fixed cells for visualization of sub-micrometer-sized spots, at the single-cell level. RiboBright reveals lineage-specific ribosome content, organization, and movement upon differentiation into either extraembryonic endoderm or ectoderm-like cells. Thus, RiboBright provides a versatile and convenient approach for imaging the cellular dynamics of ribosomes.