New evidence for differential roles of L10 ribosomal proteins from Arabidopsis

Abstract

The ribosomal protein L10 (RPL10) is an integral component of the eukaryotic ribosome large subunit. Besides being a constituent of ribosomes and participating in protein translation, additional extra-ribosomal functions in the nucleus have been described for RPL10 in different organisms. Previously, we demonstrated that Arabidopsis thaliana RPL10 genes are involved in development and translation under UV-B stress. In this work, transgenic plants expressing ProRPL10:GUS fusions show that, while AtRPL10A and AtRPL10B are expressed both in the female and male reproductive organs, AtRPL10C expression is only restricted to pollen grains. Moreover, the characterization of double rpl10 mutants indicates that the three AtRPL10 differentially contribute to the total RPL10 activity in the male gametophyte. All three AtRPL10 proteins mainly accumulate in the cytosol but also in the nucleus suggesting extra-ribosomal functions. After a UV-B treatment, only AtRPL10B localization increases in the nuclei. We also here demonstrate that the three AtRPL10 genes can complement a yeast RPL10 mutant. Finally, the involvement of RPL10B and RPL10C in UV-B responses was analyzed by 2D gels followed by mass spectrometry. Overall, our data provide new evidences about the non-redundant roles of RPL10 proteins in Arabidopsis.