Center for Systems Biology, Institute for Genome Sciences and Policy, Durham, NC 27710, USA.
BMC Genomics. 2012 Jul 30;13:351. doi: 10.1186/1471-2164-13-351.
Previous work has shown that the hypersaline-adapted archaeon, Halobacterium salinarum NRC-1, is highly resistant to oxidative stress caused by exposure to hydrogen peroxide, UV, and gamma radiation. Dynamic alteration of the gene regulatory network (GRN) has been implicated in such resistance. However, the molecular functions of transcription regulatory proteins involved in this response remain unknown.
Here we have reanalyzed several existing GRN and systems biology datasets for H. salinarum to identify and characterize a novel winged helix-turn-helix transcription factor, VNG0258H, as a regulator required for reactive oxygen species resistance in this organism. This protein appears to be unique to the haloarchaea at the primary sequence level. High throughput quantitative growth assays in a deletion mutant strain implicate VNG0258H in extreme oxidative stress resistance. According to time course gene expression analyses, this transcription factor is required for the appropriate dynamic response of nearly 300 genes to reactive oxygen species damage from paraquat and hydrogen peroxide. These genes are predicted to function in repair of oxidative damage to proteins and DNA. In vivo DNA binding assays demonstrate that VNG0258H binds DNA to mediate gene regulation.
Together these results suggest that VNG0258H is a novel archaeal transcription factor that regulates gene expression to enable adaptation to the extremely oxidative, hypersaline niche of H. salinarum. We have therefore renamed VNG0258H as RosR, for reactive oxygen species regulator.
先前的研究表明，嗜盐古菌盐杆菌 NRC-1 能够高度耐受由双氧水、UV 和伽马射线引起的氧化应激。基因调控网络（GRN）的动态变化与这种抗性有关。然而，参与该反应的转录调控蛋白的分子功能仍不清楚。
在此，我们重新分析了盐杆菌的几个现有 GRN 和系统生物学数据集，以鉴定并表征一种新型的翼螺旋-转角-螺旋转录因子 VNG0258H，它是该生物体中抵抗活性氧所必需的调节因子。该蛋白在一级序列水平上似乎是嗜盐古菌所特有的。在缺失突变株中的高通量定量生长测定表明，VNG0258H 参与极端氧化应激抗性。根据时间过程基因表达分析，该转录因子对于约 300 个基因对百草枯和双氧水引起的活性氧损伤的适当动态响应是必需的。这些基因预测在蛋白质和 DNA 的氧化损伤修复中发挥作用。体内 DNA 结合实验证明 VNG0258H 通过结合 DNA 来介导基因调控。
这些结果表明，VNG0258H 是一种新型的古菌转录因子，可调节基因表达，使盐杆菌适应其极度氧化、高盐的生态位。因此，我们将 VNG0258H 重新命名为 RosR，即活性氧调节因子。
