  Throughout the history of electron microscopy, ribosomes have served as an
ideal subject for imaging and technological development, which in turn has
driven our understanding of ribosomal biology. Here, we provide a historical
perspective at the intersection of electron microscopy technology development
and ribosome biology and reflect on how this technique has shed light on each
stage of the life cycle of this dynamic macromolecular machine. With an
emphasis on prokaryotic systems, we specifically describe how pairing cryo-EM
with clever experimental design, time-resolved techniques, and next-generation
heterogeneous structural analysis has afforded insights into the modular nature
of assembly, the roles of the many transient biogenesis and translation
co-factors, and the subtle variations in structure and function between strains
and species. The work concludes with a prospective outlook on the field,
highlighting the pivotal role cryogenic electron tomography is playing in
adding cellular context to our understanding of ribosomal life cycles, and
noting how this exciting technology promises to bridge the gap between cellular
and structural biology.
