AtnMat2, a nuclear-encoded maturase required for splicing of group-II introns in Arabidopsis mitochondria.
Mitochondria (mt) in plants house about 20 group-II introns, which lie within protein-coding genes required in both organellar genome expression and respiration activities. While in nonplant systems the splicing of group-II introns is mediated by proteins encoded within the introns themselves (known as "maturases"), only a single maturase ORF (matR) has retained in the mitochondrial genomes in plants; however, its putative role(s) in the splicing of organellar introns is yet to be established. Clues to other proteins are scarce, but these are likely encoded within the nucleus as there are no obvious candidates among the remaining ORFs within the mtDNA. Intriguingly, higher plants genomes contain four maturase-related genes, which exist in the nucleus as self-standing ORFs, out of the context of their evolutionary-related group-II introns "hosts." These are all predicted to reside within mitochondria and may therefore act "in-trans" in the splicing of organellar-encoded introns. Here, we analyzed the intracellular locations of the four nuclear-encoded maturases in Arabidopsis and established the roles of one of these genes, At5g46920 (AtnMat2), in the splicing of several mitochondrial introns, including the single intron within cox2, nad1 intron2, and nad7 intron2.
Keren
Ido
I
Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, Bet Dagan 50250, Israel.
Bezawork-Geleta
Ayenachew
A
Kolton
Max
M
Maayan
Inbar
I
Belausov
Eduard
E
Levy
Maggie
M
Mett
Anahit
A
Gidoni
David
D
Shaya
Felix
F
Ostersetzer-Biran
Oren
O
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000201:enzymology; D042541:Intracellular Space / Q000201:enzymology; D007438:Introns; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D010641:Phenotype; D012326:RNA Splicing; D018749:RNA, Plant / Q000235:genetics*; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D018749:RNA, Plant; D012194:RNA-Directed DNA Polymerase; C545659:nMat2 protein, Arabidopsis