One RNA polymerase serving two genomes.
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.
Institut für Biologie, Abteilung Genetik, Humboldt-Universität zu Berlin, Germany.
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Hedtke
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Börner
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Weihe
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004926:Escherichia coli / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate; D016678:Genome; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D010947:Plants, Toxic; D018087:Plastids / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000378:metabolism*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D008164:Luminescent Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D012321:DNA-Directed RNA Polymerases; D016650:Fluorescein-5-isothiocyanate