title: The small regulatory RNA SyR1/PsrR1 controls photosynthetic functions in cyanobacteria.
abstract: Little is known so far about RNA regulators of photosynthesis in plants, algae, or cyanobacteria. The small RNA PsrR1 (formerly SyR1) has been discovered in Synechocystis sp PCC 6803 and appears to be widely conserved within the cyanobacterial phylum. Expression of PsrR1 is induced shortly after a shift from moderate to high-light conditions. Artificial overexpression of PsrR1 led to a bleaching phenotype under moderate light growth conditions. Advanced computational target prediction suggested that several photosynthesis-related mRNAs could be controlled by PsrR1, a finding supported by the results of transcriptome profiling experiments upon pulsed overexpression of this small RNA in Synechocystis sp PCC 6803. We confirmed the interaction between PsrR1 and the ribosome binding regions of the psaL, psaJ, chlN, and cpcA mRNAs by mutational analysis in a heterologous reporter system. Focusing on psaL as a specific target, we show that the psaL mRNA is processed by RNase E only in the presence of PsrR1. Furthermore, we provide evidence for a posttranscriptional regulation of psaL by PsrR1 in the wild type at various environmental conditions and analyzed the consequences of PsrR1-based regulation on photosystem I. In summary, computational and experimental data consistently establish the small RNA PsrR1 as a regulatory factor controlling photosynthetic functions.
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Georg
authors.affiliation: Humboldt-University Berlin, Institute of Biology, 10115 Berlin, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Dienst
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Schürgers
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wallner
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Kopp
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Damir
authors.initials: D
authors.lastname: Stazic
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Kuchmina
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Klähn
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Lokstein
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany.
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Hess
authors.affiliation: University of Freiburg, Faculty of Biology, D-79104 Freiburg, Germany annegret.wilde@biologie.uni-freiburg.de.
authors.forename: Annegret
authors.initials: A
authors.lastname: Wilde
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001483:Base Sequence; D004722:Endoribonucleases / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D017930:Genes, Reporter; D006207:Half-Life; D008969:Molecular Sequence Data; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010788:Photosynthesis; D010802:Phylogeny; D011485:Protein Binding / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D004722:Endoribonucleases; C022537:ribonuclease E