The path to RNA editing in plant mitochondria: The Halifax chapter

Abstract

SummaryA single C/T difference between gene and cDNA within the 5 0 -untranslated region of the wheat mtDNA-encoded cox2 (cytochrome oxidase subunit 2) sequence catalyzed the discovery of C-to-U RNA editing in plant mitochondria by a group at Dalhousie University in Halifax, Nova Scotia [Covello and Gray, (1989) Nature 341, 662-666]. Editing of codons specifying essential copper-binding ligands in the Cox2p Cu A site provided additional insights about the amino acid residues comprising this site, as well as illustrating the functional importance of editing in wheat mitochondria. Further investigations of RNA editing in plant mitochondria led to the subsequent discovery of a case of mitochondrion-to-nucleus gene (cox2) transfer in soybean, mediated by reverse transcription of edited cox2 mRNA.

Atomic structures of respiratory complex III2, complex IV and supercomplex III2-IV from vascular plants

“…It is well established that the mRNAs of several subunits of plant respiratory complexes, including several CI subunits, CIII's COB and CIV's COX1-3, undergo cytidine-to-uridine RNA editing at several sites [50][51][52][53][54][55][56] . This mitochondrial RNA editing is widely conserved across vascular and non-vascular plants [53,57] , and most generally acts to restore consensus conserved sequences [58] .…”

“…Unfortunately, however, this conformational flexibility precluded us from building an atomic model for the head domain. Thus, we were not able to evaluate the H-bonding pattern of the QCR1 head domain with COB, or the implications of such pattern to the Q-cycle electron bifurcation mechanism [15,51,52] . Similarly, the resolution of the 3DVA was not sufficient to evaluate changes in the positions of COB's cd1 and ef helices.…”