Ribosome Profiling Reveals Translational Control During the Caulobacter crescentus cell cycle

The Caulobacter cell cycle includes sequential differentiation of the cell poles and an asymmetric cell division yielding distinct daughter cells. RNA-seq and ribosome profiling were used to measure global messenger RNA (mRNA) abundance and translation levels throughout the Caulobacter cell cycle revealing translational control in 51% of cell cycle-regulated genes. Ribosome profiling levels were temporally regulated for ten proteins encoding asymmetrically localized multi-protein assemblies that specify cell fate upon cell division, with five ORFs being regulated with a >2 fold contribution from the translation efficiency. Individual ORFs within 198 operons undergo different cell cycle patterns of translation efficiency, allowing decoupling of the expression of these co-transcribed units. This work reveals that, in addition to transcriptional control, there is prevalent translational control of cell cycle-regulated genes, providing a framework for a multi-level program of cell cycle control that generates daughter cells of different fates. Overall design: Ribosome profiling and RNA-seq data were collected in sychronized Caulobacter crescentus NA1000 cells grown in M2G to measure changes in mRNA levels and translation levels during the asymmetric cell division cycle.