PLoS Genetics (May 2016)

Mitochondrial Polyadenylation Is a One-Step Process Required for mRNA Integrity and tRNA Maturation.

  • Ana Bratic,
  • Paula Clemente,
  • Javier Calvo-Garrido,
  • Camilla Maffezzini,
  • Andrea Felser,
  • Rolf Wibom,
  • Anna Wedell,
  • Christoph Freyer,
  • Anna Wredenberg

DOI
https://doi.org/10.1371/journal.pgen.1006028
Journal volume & issue
Vol. 12, no. 5
p. e1006028

Abstract

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Polyadenylation has well characterised roles in RNA turnover and translation in a variety of biological systems. While polyadenylation on mitochondrial transcripts has been suggested to be a two-step process required to complete translational stop codons, its involvement in mitochondrial RNA turnover is less well understood. We studied knockdown and knockout models of the mitochondrial poly(A) polymerase (MTPAP) in Drosophila melanogaster and demonstrate that polyadenylation of mitochondrial mRNAs is exclusively performed by MTPAP. Further, our results show that mitochondrial polyadenylation does not regulate mRNA stability but protects the 3' terminal integrity, and that despite a lack of functioning 3' ends, these trimmed transcripts are translated, suggesting that polyadenylation is not required for mitochondrial translation. Additionally, loss of MTPAP leads to reduced steady-state levels and disturbed maturation of tRNACys, indicating that polyadenylation in mitochondria might be important for the stability and maturation of specific tRNAs.