A PPR-DYW protein is required for splicing of a group II intron of cox1 pre-mRNA in Physcomitrella patens

Plant J. 2012 Apr;70(2):271-8. doi: 10.1111/j.1365-313X.2011.04869.x. Epub 2012 Jan 10.


The pentatricopeptide repeat (PPR) protein family is involved in various steps of RNA metabolism in plastids and mitochondria. To investigate the function of a DYW sub-class PPR protein in the moss Physcomitrella patens, we constructed and characterized knockout mutants of the PpPPR_43 gene, which encodes a mitochondrial localized PPR protein with a C-terminal DYW domain. The disruptants showed poor growth of moss protonemata. To investigate whether mitochondrial transcripts were affected by disruption of PpPPR_43, we sequenced the cDNA to detect RNA editing events and performed RT-PCR analyses to measure steady-state mitochondrial transcript levels. Disruption of PpPPR_43 did not result in defective RNA editing, but a substantial reduction in the level of mature cox1 transcript was observed in the disruptants. RT-PCR analysis showed that the 3rd intron of cox1 pre-mRNA was not spliced out in the disruptants, but the 1st, 2nd and 4th introns were efficiently spliced out. This suggests that PpPPR_43 is an intron 3-specific splicing factor. The role of the C-terminal domains of PpPPR_43 in intron 3 splicing was analyzed by complementation experiments with truncated constructs lacking the DYW domain or both the E and DYW domains. Both truncated genes completely restored splicing in the PpPPR_43 knockout mutant. This indicates that the E and DYW domains of PpPPR_43 are not required for splicing, and can be deleted without loss of cox1 intron 3 splicing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Binding Sites / genetics
  • Blotting, Northern
  • Bryopsida / genetics*
  • Bryopsida / metabolism
  • Electron Transport Complex IV / genetics*
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Introns / genetics*
  • Mitochondria / genetics
  • Mitochondria / metabolism
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • Molecular Sequence Data
  • Mutation
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Protein Subunits / genetics
  • RNA / genetics
  • RNA / metabolism
  • RNA Precursors / genetics*
  • RNA Precursors / metabolism
  • RNA Splicing*
  • RNA, Mitochondrial
  • Reverse Transcriptase Polymerase Chain Reaction


  • Mitochondrial Proteins
  • Plant Proteins
  • Protein Subunits
  • RNA Precursors
  • RNA, Mitochondrial
  • Green Fluorescent Proteins
  • RNA
  • Electron Transport Complex IV

Associated data

  • GENBANK/AB675532