Phage-type RNA polymerase RPOTmp performs gene-specific transcription in mitochondria of Arabidopsis thaliana.
Transcription of mitochondrial genes in animals, fungi, and plants relies on the activity of T3/T7 phage-type RNA polymerases. Two such enzymes, RPOTm and RPOTmp, are present in the mitochondria of eudicotyledonous plants; RPOTmp is additionally found in plastids. We have characterized the transcriptional role of the dual-targeted RNA polymerase in mitochondria of Arabidopsis thaliana. Examination of mitochondrial transcripts in rpoTmp mutants revealed major differences in transcript abundances between wild-type and rpoTmp plants. Decreased levels of specific transcripts were correlated with reduced abundances of the respiratory chain complexes I and IV. Altered transcript levels in rpoTmp were found to result from gene-specific transcriptional changes, establishing that RPOTmp functions in distinct transcriptional processes within mitochondria. Decreased transcription of specific genes in rpoTmp was not associated with changes in promoter utilization; therefore, RPOTmp function is not promoter specific but gene specific. This implies that additional gene-specific elements direct the transcription of a subset of mitochondrial genes by RPOTmp.
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, WA, Australia. kristina@cyllene.uwa.edu.au
Kristina
K
Kühn
Uwe
U
Richter
Etienne H
EH
Meyer
Etienne
E
Delannoy
Andéol Falcon
AF
de Longevialle
Nicholas
N
O'Toole
Thomas
T
Börner
A Harvey
AH
Millar
Ian D
ID
Small
James
J
Whelan
D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D050259:Genes, Mitochondrial; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D011401:Promoter Regions, Genetic; D018749:RNA, Plant / Q000235:genetics; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D024101:Mitochondrial Proteins; D018749:RNA, Plant; C036483:T-DNA; D012321:DNA-Directed RNA Polymerases; C526985:RpoTmp protein, Arabidopsis