The one-component system ArnR: a membrane-bound activator of the crenarchaeal archaellum
The one-component system ArnR: a membrane-bound activator of the crenarchaeal archaellum
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DOI：
10.1111/mmi.12173
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发表时间：
2013-04-01
影响因子：
3.6
通讯作者：
Albers, Sonja-Verena
中科院分区：
文献类型：
--
作者：
Lassak, Kerstin;Peeters, Eveline;Albers, Sonja-Verena
将运动装置与信号转导系统连接起来，使微生物能够根据环境条件精确地控制它们的游泳行为。因此，细菌已经进化出一种复杂的趋化机制，这种机制可能是通过横向基因转移传播到广古菌亚界的。相比之下，Crenarchaeota编码没有趋化性样蛋白，但仍然能够连接外部刺激古菌衍生的运动。这就提出了有关基本监管机制的根本问题。最近，我们报道了嗜热嗜酸泉古菌Sulfolobus acidocaldarius通过促进编码丝状体形成亚基的flaB的转录而在营养饥饿时变得能动。在这里，我们描述了两个转录激活子作为旁系同源的单组分系统Saci_1180和Saci_1171（ArnR和ArnR1）。arnR和arnR1的缺失导致flaB表达减少，因此缺失突变体显示游泳运动受损。我们进一步确定了两个反向重复序列位于上游的flaB核心启动子的S.acidocaldarius。这些顺式调控元件被证明是至关重要的ArnR和ArnR1介导的flaB基因在体内的表达。最后，生物信息学分析显示，ArnR不仅在Sulfolobales中，而且在Desulfurococcales的crenarchaeal中也是保守的，因此可能代表了古菌运动的更一般的控制机制。
Linking the motility apparatus to signal transduction systems enables microbes to precisely control their swimming behaviour according to environmental conditions. Bacteria have therefore evolved a complex chemotaxis machinery, which has presumably spread through lateral gene transfer into the euryarchaeal subkingdom. By contrast Crenarchaeota encode no chemotaxis-like proteins but are nevertheless able to connect external stimuli to archaellar derived motility. This raises fundamental questions about the underlying regulatory mechanisms. Recently, we reported that the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius becomes motile upon nutrient starvation by promoting transcription of flaB encoding the filament forming subunits. Here we describe two transcriptional activators as paralogous one-component-systems Saci_1180 and Saci_1171 (ArnR and ArnR1). Deletions of arnR and arnR1 resulted in diminished flaB expression and accordingly the deletion mutants revealed impaired swimming motility. We further identified two inverted repeat sequences located upstream of the flaB core promoter of S.acidocaldarius. These cis-regulatory elements were shown to be critical for ArnR and ArnR1 mediated flaB gene expression in vivo. Finally, bioinformatic analysis revealed ArnR to be conserved not only in Sulfolobales but also in the crenarchaeal order of Desulfurococcales and thus might represent a more general control mechanism of archaeal motility.