A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Inorganic carbon levels regulate growth via SigC signaling cascade in cyanobacteria
Tekijät: Kurkela, Juha; Vuorijoki, Linda; Vakal, Serhii; Turunen, Otso; Koskinen, Satu; Reimann, Viktoria; Ray, Mithila; Hess, Wolfgang R.; Salminen, Tiina A.; Tyystjärvi, Taina
Kustantaja: Wiley
Kustannuspaikka: HOBOKEN
Julkaisuvuosi: 2025
Journal: New Phytologist
Tietokannassa oleva lehden nimi: New Phytologist
Lehden akronyymi: NEW PHYTOL
Artikkelin numero: nph.70328
Sivujen määrä: 16
ISSN: 0028-646X
eISSN: 1469-8137
DOI: https://doi.org/10.1111/nph.70328
Verkko-osoite: https://doi.org/10.1111/nph.70328
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/499077929
Cyanobacterial growth depends on inorganic carbon (Ci; CO2 and bicarbonate) concentration, but mechanism(s) adjusting photosynthesis and growth according to Ci remain unclear. Delta rpoZ cells lacking the omega subunit of the RNA polymerase (RNAP) show a unique high-CO2 lethal phenotype in Synechocystis sp. PCC 6803.
Bioinformatics, biochemical and 3D modeling studies were used to reveal how suppressor mutations rescue Delta rpoZ cells in 3% CO2.
Suppressor mutations were mapped to the ssr1600 gene. Ssr1600 was shown to function as an anti-sigma factor antagonist. The Slr1861 protein was identified as an anti-sigma factor and as an Ssr1600 kinase. The Slr1861/Ssr1600 pair was shown to control the formation of RNAP-SigC holoenzyme using a phosphorylation-controlled partner-switching mechanism. In high CO2, excess formation of growth-limiting RNAP-SigC holoenzyme in Delta rpoZ reduces the expression of cell wall synthesis, photosynthetic and nutrient uptake genes, leading to low photosynthesis activity and cell lysis. In the suppressor mutants, drastically decreased Ssr1600 levels lowered the amounts of RNAP-SigC holoenzyme to similar levels as in the control strain, returning an almost normal transcriptome composition, photosynthesis and growth.
The results indicate that SigC, Slr1861 and Ssr1600 proteins form a growth-regulating signaling cascade in cyanobacteria, which connects growth to environmental Ci levels.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
Julkaisussa olevat rahoitustiedot:
We appreciate the financial support by the Research Council of Finland (grant no. 347172) and Novo Nordisk Foundation (grant nos. NNF19OC0057660 and NNF22OC007984) to TT, Finnish Cultural Foundation (grant no. 00190580) to JK, Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through the FOR2816 research group 'SCyCode' to WRH (grant no. HE 2544/15-2). We thank Prof. Munehiko Asayama, University of Ibaraki, and Dr Marion Eisenhut, Bielefeld University, for a generous gift of group 3 sigma factor antibodies and plasmid pAII:Sm, respectively. We thank Dr. Esa Tyystjaervi and Prof. Paula Mulo for their useful comments. The Finnish Infrastructure for Photosynthesis Research PHOTOSYN is acknowledged for the excellent research facilities. The live cell imaging was performed in the Cell Imaging and Cytometry Core of Turku Bioscience, and the authors especially thank Dr Jouko Sandholm for all advice. We thank Turku Protein Core for helping with large-scale protein purification. We are grateful to the bioinformatics (JV Lehtonen), translational activities and structural biology infrastructure (FINStruct) support from Biocenter Finland and CSC IT Center for Science for computational infrastructure support at the Structural Bioinformatics Laboratory, abo Akademi University. Open access publishing facilitated by Turun yliopisto, as part of the Wiley - FinELib agreement.
