Turunen Otso, Koskinen Satu, Kurkela Juha, Karhuvaara Outi, Hakkila Kaisa, Tyystjärvi Taina
Molecular Plant Biology, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland.
Life (Basel). 2022 Jan 21;12(2):162. doi: 10.3390/life12020162.
Acclimation of cyanobacterium sp. PCC6803 to suboptimal conditions is largely dependent on adjustments of gene expression, which is highly controlled by the σ factor subunits of RNA polymerase (RNAP). The SigB and SigD σ factors are close homologues. Here we show that the and genes are both induced in high light and heat stresses. Comparison of transcriptomes of the control strain (CS), ΔsigB, ΔsigD, ΔsigBCE (containing SigD as the only functional group 2 σ factor), and ΔsigCDE (SigB as the only functional group 2 σ factor) strains in standard, high light, and high temperature conditions revealed that the SigB and SigD factors regulate different sets of genes and SigB and SigD regulons are highly dependent on stress conditions. The SigB regulon is bigger than the SigD regulon at high temperature, whereas, in high light, the SigD regulon is bigger than the SigB regulon. Furthermore, our results show that favoring the SigB or SigD factor by deleting other group 2 σ factors does not lead to superior acclimation to high light or high temperature, indicating that all group 2 σ factors play roles in the acclimation processes.
蓝藻菌株PCC6803对次优条件的适应在很大程度上依赖于基因表达的调整，而基因表达受到RNA聚合酶（RNAP）的σ因子亚基的高度控制。SigB和SigD σ因子是密切的同源物。在这里，我们表明 和 基因在高光和热胁迫下均被诱导。对对照菌株（CS）、ΔsigB、ΔsigD、ΔsigBCE（仅含SigD作为唯一功能性第2组σ因子）和ΔsigCDE（仅含SigB作为唯一功能性第2组σ因子）在标准、高光和高温条件下的转录组进行比较，结果显示SigB和SigD因子调控不同的基因集，并且SigB和SigD调控子高度依赖于胁迫条件。在高温下，SigB调控子比SigD调控子大，而在高光条件下，SigD调控子比SigB调控子大。此外，我们的结果表明，通过删除其他第2组σ因子来偏向SigB或SigD因子并不会导致对高光或高温的更好适应，这表明所有第2组σ因子在适应过程中都发挥作用。
