SMK6 mediates the C-to-U editing at multiple sites in maize mitochondria

J Plant Physiol. 2019 Sep:240:152992. doi: 10.1016/j.jplph.2019.152992. Epub 2019 Jun 8.

Abstract

The recently identified PPR-E+/NVWA/DYW2 RNA editing complex provides insights into the mechanism of RNA editing in higher plant organelles. However, whether the complex works together with the previously identified editing factors RIPs/MORFs is unclear. In this paper, we identified a maize Smk6 gene, which encodes a mitochondrion-targeted PPR-E+protein with E1 and E2 domains at the C terminus. Loss of Smk6 function affects the C-to-U editing at nad1-740, nad4L-110, nad7-739, and mttB-138,139 sites, impairs mitochondrial activity and blocks embryogenesis and endosperm development. Genetic and molecular analysis indicated that SMK6 is the maize ortholog of the Arabidopsis SLO2, which is a component of the PPR-E+/NVWA/DYW2 editing complex. However, yeast two-hybrid analyses did not detect any interaction between SMK6 and any of the mitochondrion-targeted RIPs/MORFs, suggesting that RIPs/MORFs may not be a component of PPR-E+/NVWA/DYW2 RNA editing complex. Further analyses are required to provide evidence that RIP/MORFs and SMK6 do not physically interact in vivo.

Keywords: Editing; Mitochondria; PPR protein; RIPs/MORFs; SMK6.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Gene Expression Regulation, Plant*
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • RNA Editing*
  • Sequence Alignment
  • Zea mays / genetics*
  • Zea mays / metabolism

Substances

  • Mitochondrial Proteins
  • Plant Proteins