Regulation of σB-dependent transcription of sigB and asp23 in two different Staphylococcus aureus strains
Regulation of σB-dependent transcription of sigB and asp23 in two different Staphylococcus aureus strains
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DOI：
10.1007/s004380051001
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发表时间：
1999-04-01
期刊：
影响因子：
--
通讯作者：
Hecker, M
中科院分区：
文献类型：
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作者：
Gertz, S;Engelmann, S;Hecker, M
碱性休克蛋白Asp23在金黄色葡萄球菌中被鉴定为sigma(B)依赖性蛋白。在枯草芽孢杆菌中，金黄色葡萄球菌的asp23启动子与其他sigma(B)依赖性启动子一样受到调控，这些启动子受到高温和乙醇胁迫的强烈诱导。然而，在合成培养基中培养的金黄色葡萄球菌MA13在高温或乙醇胁迫下几乎没有诱导asp23的表达，而合成培养基中asp23的基础表达水平较高。在相同的实验条件下，sigma(B)基因本身表现出类似的表达模式：在合成培养基中高表达，但不受高温或乙醇胁迫的诱导。相反，当细胞在复杂培养基中生长时，热应激增加了sigma(B)活性。在合成培养基中培养的金黄色葡萄球菌MA13中sigB和sigma(B)依赖性应激基因的组成性表达与枯草芽孢杆菌对sigma(B)活性的调控形成鲜明对比，需要进一步研究。在葡萄球菌NCTC 8325-4中，编码作用于RsbV的磷酸酶（抗-抗sigma因子）的rsbU基因缺失了11 bp，这可能是导致该菌株在复杂培养基中热应激无法激活sigma(B)的原因，从而减少了sigma(B)依赖启动子的转录起始。
The alkaline shock protein Asp23 was identified as a sigma(B)-dependent protein in Staphylococcus aureus. In Bacillus subtilis, the asp23 promoter from S. aureus is regulated like other sigma(B)-depondent promoters, which are strongly induced by heat and ethanol stress. However, almost no induction of asp23 expression was found after heat or ethanol stress in S, aureus MA13 grown in a synthetic medium, where the basal expression level of asp23 is high. Under the same experimental conditions the sigma(B) gene itself showed a similar expression pattern: it was highly expressed in synthetic medium but not induced by heat or ethanol stress. In contrast, sigma(B) activity was increased by heat stress when the cells were grown in a complex medium. The constitutive expression of sigB and sigma(B)-dependent stress genes in S. aureus MA13 grown in a synthetic medium is in a sharp contrast to the regulation of sigma(B) activity in B. subtilis, and needs further investigation. A deletion of 11 bp in the rsbU gene, which encodes the phosphatase that acts on RsbV (the anti-anti-sigma factor), in S. aureus NCTC 8325-4 might be responsible for the failure of heat stress to activate sigma(B) in complex medium, and thus reduce the initiation of transcription at sigma(B)-dependent promoters in this strain.