Arabidopsis REI-LIKE proteins activate ribosome biogenesis during cold acclimation

Abstract

AbstractArabidopsis REIL proteins are cytosolic ribosomal 60S-biogenesis factors. After shift to 10°C,reilmutants deplete and slowly replenish non-translating eukaryotic ribosome complexes of root tissue, while tightly controlling the balance of non-translating 40S- and 60S-subunits.Reilmutations compensate by hyper-accumulation of non-translating subunits at steady-state temperature; after cold-shift, a KCl-sensitive 80S sub-fraction remains depleted. We infer that Arabidopsis buffers fluctuating translation by pre-existing non-translating ribosomes beforede novosynthesis meets temperature-induced demands.Reil1 reil2double mutants accumulate 43S-preinitiation and pre-60S-maturation complexes and have altered paralog composition of ribosomal proteins in non-translating complexes. With few exceptions, e.g. RPL3B and RPL24C, these changes are not under transcriptional control. Our study suggests requirement ofde novosynthesis of eukaryotic ribosomes for long-term cold acclimation, feedback control ofNUC2andeIF3C2transcription and links new proteins, AT1G03250, AT5G60530, to plant ribosome biogenesis. We propose that Arabidopsis requires biosynthesis of specialized ribosomes for cold acclimation.Highlight of this studyREIL proteins affect paralog composition of eukaryotic ribosomes and suppress accumulation of 43S-preinitiation and pre-60S-maturation complexes, suggesting functions of ribosome heterogeneity and biogenesis in plant cold acclimation.