title: Chloroplast RNA polymerases: Role in chloroplast biogenesis.
abstract: Plastid genes are transcribed by two types of RNA polymerase in angiosperms: the bacterial type plastid-encoded RNA polymerase (PEP) and one (RPOTp in monocots) or two (RPOTp and RPOTmp in dicots) nuclear-encoded RNA polymerase(s) (NEP). PEP is a bacterial-type multisubunit enzyme composed of core subunits (coded for by the plastid rpoA, rpoB, rpoC1 and rpoC2 genes) and additional protein factors (sigma factors and polymerase associated protein, PAPs) encoded in the nuclear genome. Sigma factors are required by PEP for promoter recognition. Six different sigma factors are used by PEP in Arabidopsis plastids. NEP activity is represented by phage-type RNA polymerases. Only one NEP subunit has been identified, which bears the catalytic activity. NEP and PEP use different promoters. Many plastid genes have both PEP and NEP promoters. PEP dominates in the transcription of photosynthesis genes. Intriguingly, rpoB belongs to the few genes transcribed exclusively by NEP. Both NEP and PEP are active in non-green plastids and in chloroplasts at all stages of development. The transcriptional activity of NEP and PEP is affected by endogenous and exogenous factors. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
authors: Institute of Biology-Genetics, Humboldt University, Chausseestr. 117, 10115 Berlin, Germany. Electronic address: thomas.boerner@rz.hu-berlin.de.
authors: Thomas
authors: T
authors: Börner
authors: Institute of Biology-Genetics, Humboldt University, Chausseestr. 117, 10115 Berlin, Germany; Timiriazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia.
authors: Anastasia Yu
authors: AY
authors: Aleynikova
authors: Institute of Biology-Genetics, Humboldt University, Chausseestr. 117, 10115 Berlin, Germany.
authors: Yan O
authors: YO
authors: Zubo
authors: Timiriazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia.
authors: Victor V
authors: VV
authors: Kusnetsov
mesh_terms: D002736:Chloroplasts / Q000235:genetics / Q000502:physiology*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000502:physiology*; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
chemical_list: D012321:DNA-Directed RNA Polymerases
keywords: Chloroplast RNA; Chloroplast RNA polymerase; Chloroplast biogenesis; Chloroplast development; Chloroplast transcription; Photosynthesis