A1 Journal article – refereed
In vivo recruitment analysis and a mutant strain without any group 2 sigma factor reveal roles of different sigma factors in cyanobacteria




List of Authors: Koskinen S, Hakkila K, Gunnelius L, Kurkela J, Wada H, Tyystjarvi T
Publisher: WILEY-BLACKWELL
Publication year: 2016
Journal: Molecular Microbiology
Journal name in source: MOLECULAR MICROBIOLOGY
Journal acronym: MOL MICROBIOL
Volume number: 99
ISSN: 0950-382X

Abstract


In eubacteria, replacement of one sigma factor in the RNA polymerase (RNAP) holoenzyme by another one changes the transcription pattern. Cyanobacteria are eubacteria characterized by oxygenic photosynthesis, and they typically encode numerous group 2 sigma factors that closely resemble the essential primary sigma factor. A mutant strain of the model cyanobacterium Synechocystis sp. PCC 6803 without functional group 2 s factors (named as.sigBCDE) could not acclimate to heat, high salt or bright light stress, but in standard conditions.sigBCDE grew only 9% slower than the control strain. One-fifth of the genes in.sigBCDE was differently expressed compared with the control strain in standard growth conditions and several physiological changes in photosynthesis, and pigment and lipid compositions were detected. To directly analyze the s factor content of RNAP holoenzyme in vivo, a His-tag was added to the. subunit of RNAP in Synechocystis and RNAPs were collected. The results revealed that all group 2 sigma factors were recruited by RNAP in standard conditions, but recruitment of SigB and SigC increased in heat stress, SigD in bright light, SigE in darkness and SigB, SigC and SigE in high salt, explaining the poor acclimation of Delta sigBCDE to these stress conditions.



Last updated on 2019-20-07 at 14:24