Figure 2.
Panel A shows experimental changes in ribosome assembly, such as knockout of ribosomal proteins, assembly factors, or snoRNAs, leading to altered ribosomes and reduced ribosome numbers. Panel B illustrates the tagging of ribosomal proteins, which can perturb ribosome function and affect mRNA recruitment or ribosome numbers. Panel C: Illustration of attenuated translation rates in nutrient-depleted (starved) or contact-inhibited (confluent) cells, which serves to artificially maintain ribosomal heterogeneity. Panel D: Depiction of programmed or adaptive modifications within the translational apparatus that trigger downstream compensatory genetic or epigenetic remodeling.
Situations that must be addressed by control experiments. (A) Most alterations in the ribosome assembly machinery (including the deletion of snoRNAs) produce both altered ribosomes (in orange), as well as reduced ribosome numbers, which both can have mRNA-specific effects on translation. (B) Tagging of RPs can perturb ribosome function, affecting mRNA recruitment, or ribosome numbers, thereby affecting translation in an mRNA-specific manner. (C) Reduced translation in starved or confluent cells will preclude collisions, preserving ribosome heterogeneity artificially. (D) Alterations in the translational machinery can lead to compensatory genetic or epigenetic changes.