MPI-MP WINTER SERIES: Impact of altered ribosomes on translation and RNA maturation in plant mitochondria - Hanna Jańska

MPI-MP Winter Series

  • Date: Dec 8, 2021
  • Time: 02:00 PM - 03:30 PM (Local Time Germany)
  • Speaker: Hanna Jańska
  • Location: Zoom
  • Host: PostDoc-Representatives @MPI-MP
  • Contact: Lonoce@mpimp-golm.mpg.de

Ribosomes are not simple nonselective translation machines, but may also function as regulatory elements in translation, and based on our recent results, they can also influence RNA maturation. We found that silencing of the nuclear RPS10 gene encoding the mitochondrial ribosomal S10 protein in Arabidopsis affects the biogenesis of mitoribosomes leading to their distinct conformation. The altered S10-deficient mitoribosomes protect shorter transcript fragments which exhibit a weaker 3-nt periodicity compared with the wild-type. In consequence, subset of preferentially translatable mRNAs is changed. The wild-type mitoribosomes preferentially synthesize OXPHOS proteins while the rps10 mitoribosomes show slightly reduced translation efficiency of most respiration-related proteins, but at the same time markedly more efficiently synthesize ribosomal proteins,MatR and TatC proteins. We also unexpectedly found that RNA maturation processes like intron splicing, editing, 3’-end processing of some transcripts were less efficient in the rps10 mutant compared with the wild-type. Moreover, we observed significant accumulation of small RNAs and RNA-seq reads form the intergenic regions in the rps10 mutant. Our new results suggest that most of the observed changes in RNA metabolism in rps10 could be associated with the changed assembly status of complexes formed by polynucleotide phosphorylase (mtPNPase), a crucial multifunctional enzyme in RNA homeostasis and decay in plant mitochondria. Our working hypothesis is that in plant mitochondria there is a spatial interaction between the translation and RNA maturation machineries.

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