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Updated: Aug 11, 2026

mRNA Interactome Capture from Plant Protoplasts
Published on: July 28, 2017
Regulation of plastid rDNA transcription by interaction of CDF2 with two different RNA polymerases
M Bligny1, F Courtois, S Thaminy
1Laboratoire de Génétique Moléculaire des Plantes, Université Joseph Fourier and Centre National de la Recherche Scientifique, BP 53X, F-38041 Grenoble, France.
Abstract:
The plastid genome is known to be transcribed by a plastid-encoded prokaryotic-type RNA polymerase (PEP) and by a nucleus-encoded phage-type RNA polymerase (NEP). The spinach plastid rrn operon promoter region harbours three different, overlapping promoters. Two of them are of the prokaryotic type. The third promoter is a non-consensus-type NEP promoter. We separated three different transcriptional activities from spinach chloroplasts: PEP, the phage-type RNA polymerase NEP-1, and a third, hitherto undescribed transcriptional activity (NEP-2). NEP-2 specifically transcribes the rrn operon in the presence of the transcription factor CDF2. CDF2 was previously shown to recruit PEP to the rrn promoter to repress transcription. Together, our results suggest the existence of a third RNA polymerase in plastids and a mechanism of rDNA transcriptional regulation that is based on the interaction of the transcription factor CDF2 with two different transcriptional systems.
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