Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
J Bacteriol. 2010 Feb;192(3):755-62. doi: 10.1128/JB.00826-09. Epub 2009 Nov 30.
The sigma(B)-dependent general stress response in the common soil bacterium Bacillus subtilis can be elicited by a range of stress factors, such as starvation or an ethanol, salt, or heat shock, via a complex upstream signaling cascade. Additionally, sigma(B) can be activated by blue light via the phototropin homologue YtvA, a component of the environmental branch of the signaling cascade. Here we use a reporter-gene fusion to show that sigma(B) can also be activated by red light via the energy branch of its upstream signaling cascade. Deletion mutagenesis and homologous overproduction experiments indicate that the RsbP protein (composed of an N-terminal Per-ARNT-Sim [PAS] domain and a C-terminal PP2C-type phosphatase domain) is involved in the red light response. This second light input pathway functions complementarily to YtvA; it shows broader spectral sensitivity but requires higher light intensities. These results are confirmed by transcriptome analyses, which show that both light effects result in upregulation of the sigma(B) regulon, with minimal activation of other responses.
在常见土壤细菌枯草芽孢杆菌中，σ(B)依赖的一般应激反应可以通过一系列应激因素（如饥饿或乙醇、盐或热休克）通过复杂的上游信号级联来引发。此外，σ(B)可以通过蓝光激活，蓝光通过光受体同源物 YtvA 激活，YtvA 是信号级联的环境分支的一个组成部分。在这里，我们使用报告基因融合来表明 σ(B)也可以通过其上游信号级联的能量分支被红光激活。缺失突变和同源过表达实验表明，RsbP 蛋白（由 N 端 Per-ARNT-Sim [PAS] 结构域和 C 端 PP2C 型磷酸酶结构域组成）参与了红光反应。这个第二个光输入途径与 YtvA 互补；它显示出更广泛的光谱灵敏度，但需要更高的光强度。这些结果通过转录组分析得到证实，转录组分析表明，这两种光效应都导致了 σ(B)调控物的上调，而其他反应的激活最小。
