Whole-Genome Microarray and Gene Deletion Studies Reveal Regulation of the Polyhydroxyalkanoate Production Cycle by the Stringent Response in Ralstonia eutropha H16
Whole-Genome Microarray and Gene Deletion Studies Reveal Regulation of the Polyhydroxyalkanoate Production Cycle by the Stringent Response in Ralstonia eutropha H16
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DOI：
10.1128/aem.01693-12
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发表时间：
2012-11-01
影响因子：
4.4
通讯作者：
Sinskey, Anthony J.
中科院分区：
文献类型：
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作者：
Brigham, Christopher J.;Speth, Daan R.;Sinskey, Anthony J.
聚（3-羟基丁酸）（PHB）的生产和动员在Ralstonia eutropha中得到了很好的研究，但在少数情况下，PHB的生产与其他细胞过程有关。我们检测了野生型真菌在整个PHB循环中的全球基因表达：在果糖上生长，在铵耗尽后利用果糖生产PHB，以及在铵补充后缺乏外源碳时PHB的利用。我们的结果证实或支持先前报道的关于phb相关基因和酶表达的结果。此外，许多不同细胞过程的基因，如DNA复制、细胞分裂和翻译，在PHB的产生过程中被选择性地抑制。相反，受备选sigma因子sigma（54）控制的基因表达水平在PHB产生过程中急剧上升，在PHB利用过程中再次受到抑制。PHB产生过程中的全球基因调控与其他物种在严格反应过程中观察到的基因表达模式非常相似。此外，ppGpp合成酶缺失突变体没有显示PHB的积累，与dl -正缬氨酸的严格反应的化学诱导导致在铵存在下PHB的积累增加。这些结果表明，PHB在真菌丝中积累需要严格的反应，有助于阐明这一过程迄今未知的生理基础。
Poly(3-hydroxybutyrate) (PHB) production and mobilization in Ralstonia eutropha are well studied, but in only a few instances has PHB production been explored in relation to other cellular processes. We examined the global gene expression of wild-type R. eutropha throughout the PHB cycle: growth on fructose, PHB production using fructose following ammonium depletion, and PHB utilization in the absence of exogenous carbon after ammonium was resupplied. Our results confirm or lend support to previously reported results regarding the expression of PHB-related genes and enzymes. Additionally, genes for many different cellular processes, such as DNA replication, cell division, and translation, are selectively repressed during PHB production. In contrast, the expression levels of genes under the control of the alternative sigma factor sigma(54) increase sharply during PHB production and are repressed again during PHB utilization. Global gene regulation during PHB production is strongly reminiscent of the gene expression pattern observed during the stringent response in other species. Furthermore, a ppGpp synthase deletion mutant did not show an accumulation of PHB, and the chemical induction of the stringent response with DL-norvaline caused an increased accumulation of PHB in the presence of ammonium. These results indicate that the stringent response is required for PHB accumulation in R. eutropha, helping to elucidate a thus-far-unknown physiological basis for this process.