Abstract
SUMMARYATP-Binding Cassette E (ABCE) proteins dissociate cytoplasmic ribosomes after translation terminates, and contribute to ribosome recycling, thus linking translation termination to initiation. This function has been demonstrated to be essential in animals, fungi, and archaea, but remains unexplored in plants.In most species, ABCE is encoded by a single-copy gene; by contrast,Arabidopsis thalianahas twoABCEparalogs, of whichABCE2seems to conserve the ancestral function. We isolatedapiculata7-1 (api7-1), a viable, hypomorphic allele ofABCE2,which has a pleiotropic morphological phenotype reminiscent of mutations affecting ribosome biogenesis factors and ribosomal proteins. We also studiedapi7-2, a null, recessive lethal allele ofABCE2.Co-immunoprecipitation experiments showed that ABCE2 physically interacts with components of the translation machinery. An RNA-seq study of theapi7-1mutant showed increased responses to iron and sulfur starvation. We also found increased transcript levels of genes related to auxin signaling and metabolism.Our results support a conserved role for ABCE proteins in ribosome recycling in plants, as previously shown for the animal, fungal, and archaeal lineages. In plants, the ABCE2 protein seems important for general growth and vascular development, likely due to an indirect effect through auxin metabolism.
Publisher
Cold Spring Harbor Laboratory