title: Plastid sigma factors: Their individual functions and regulation in transcription.
abstract: Sigma factors are the predominant factors involved in transcription regulation in bacteria. These factors can recruit the core RNA polymerase to promoters with specific DNA sequences and initiate gene transcription. The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. Although all plastid sigma factors contain sequences conserved in bacterial sigma factors, a considerable number of distinct traits have been acquired during evolution. The present review summarises recent advances concerning the regulation of the structure, function and activity of plastid sigma factors since their discovery nearly 40 years ago. We highlight the specialised roles and overlapping redundant functions of plastid sigma factors according to their promoter selectivity. We also focus on the mechanisms that modulate the activity of sigma factors to optimise plastid function in response to developmental cues and environmental signals. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. Electronic address: chiweimr@ibcas.ac.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Chi
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Baoye
authors.initials: B
authors.lastname: He
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Mao
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D018087:Plastids / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D012808:Sigma Factor
keywords: Plastid; Plastid-encoded RNA polymerase; Sigma factor; Transcription