Expression of a stress- and starvation-induced dps/pexB-homologous gene is controlled by the alternative sigma factor sigma(B) in Bacillus subtilis
Expression of a stress- and starvation-induced dps/pexB-homologous gene is controlled by the alternative sigma factor sigma(B) in Bacillus subtilis
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DOI：
10.1128/jb.179.23.7251-7256.1997
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发表时间：
1997-12-01
影响因子：
3.2
通讯作者：
Hecker, M
中科院分区：
文献类型：
--
作者：
Antelmann, H;Engelmann, S;Hecker, M
枯草芽孢杆菌依赖于Sigma(6)的一般应激蛋白(G：SPS)在葡萄糖胁迫诱导的对氧化挑战的交叉抗性的形成中是必不可少的。然而，直接参与这种对氧化应激的非特异性抵抗的蛋白质必须得到鉴定。我们发现一个显著的GSP与先前描述的枯草杆菌氧化应激诱导的MRGA蛋白以及大肠杆菌饥饿诱导的DPS/PexB蛋白具有很强的序列相似性。因此，我们指定这一突出的普惠制DPS。MRGA属于过氧化氢诱导的氧化应激适应性反应所需的过氧化应激诱导蛋白，而DPS属于热、盐、乙醇胁迫和葡萄糖饥饿后诱导的蛋白质，而不是亚致死性的氧化挑战。引物延伸实验发现，DPS编码区上游有两个重叠的启动子，一个依赖于西格玛(B)(P-B)，另一个不依赖西格玛(B)(P-1)。这两个启动子在生长过程中都对DPS的基础水平做出了贡献。应激后或进入稳定期时，P-B的转录显著增加，而P-1的转录减少。缺乏DPS的突变菌株完全不能形成葡萄糖饥饿诱导的对氧化应激的抗性。这些结果证实了我们的假设，即枯草杆菌非特异性抗氧化性的发展绝对需要依赖于Sigma(B)的一般应激蛋白。
sigma(6)-dependent general stress proteins (G:sps) of Bacillus subtilis are essential for the development of glucose-stravation-induced cross-resistance to oxidative challenge. However, the proteins directly involved in this nonspecific resistance to oxidative stress have to be identified. We found that one prominent Gsp displayed strong sequence similarity to the previously characterised oxidative-stress-inducible MrgA protein of B. subtilis and to the starvation-induced Dps/PexB protein of Escherichia coli. We therefore designated this prominent Gsp Dps. While MrgA belongs to the peroxide-stress-inducible proteins needed for the H2O2-inducible adaptive response to oxidative stress, Dps belongs to the proteins induced by heat, salt, or ethanol stress and after starvation for glucose but not by a sublethal oxidative challenge. Primer extension experiments identified two overlapping promoters upstream of the coding region of dps, one being sigma(B) dependent (P-B) and the other being sigma(B) independent (P-1). Both promoters contribute to the basal level of dps during growth. After stress or during entry into the stationary phase, transcription from P-B strongly increased whereas transcription from P-1 decreased. Mutant strains lacking Dps completely failed to develop glucose-starvation-induced resistance to oxidative stress. These results confirm our suggestion that sigma(B)-dependent general stress proteins of B. subtilis are absolutely required for the development of nonspecific resistance to oxidative stress.