One RNA polymerase serving two genomes

EMBO Rep. 2000 Nov;1(5):435-40. doi: 10.1093/embo-reports/kvd086.


The land plant Arabidopsis thaliana contains three closely related nuclear genes encoding phage-type RNA polymerases (RpoT;1, RpoT;2 and RpoT;3). The gene products of RpoT;1 and RpoT;3 have previously been shown to be imported into mitochondria and chloroplasts, respectively. Here we show that the transit peptide of RpoT;2 possesses dual targeting properties. Transient expression assays in tobacco protoplasts as well as stable transformation of Arabidopsis plants demonstrate efficient targeting of fusion peptides consisting of the N-terminus of RpoT;2 joined to green fluorescent protein to both organelles. Thus, RpoT;2 might be the first RNA polymerase shown to transcribe genes in two different genomes. RNA polymerase activity of recombinant RpoT;2 is uneffected by the inhibitor tagetin, qualifying the gene product of RpoT;2 as a phage-type polymerase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics*
  • Cloning, Molecular
  • DNA, Complementary / metabolism
  • DNA-Directed RNA Polymerases / genetics
  • DNA-Directed RNA Polymerases / metabolism
  • DNA-Directed RNA Polymerases / physiology*
  • Escherichia coli / metabolism
  • Fluorescein-5-isothiocyanate
  • Genome*
  • Green Fluorescent Proteins
  • Luminescent Proteins / metabolism
  • Microscopy, Fluorescence
  • Mitochondria / metabolism
  • Models, Genetic
  • Molecular Sequence Data
  • Peptides / metabolism*
  • Plants, Toxic*
  • Plastids / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Tobacco / metabolism*
  • Transcription, Genetic*


  • DNA, Complementary
  • Luminescent Proteins
  • Peptides
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • DNA-Directed RNA Polymerases
  • Fluorescein-5-isothiocyanate

Associated data

  • GENBANK/AJ278248