Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
Medical Microbiology and Bioprocess Technology Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana, India.
J Cell Biochem. 2018 Jul;119(7):5761-5774. doi: 10.1002/jcb.26751. Epub 2018 Mar 14.
Microbial colonization is an outcome of appropriate sensing and regulation of its gene expression. Bacillus anthracis adapts and thrives in its environment through complex regulatory mechanisms, among them, the two component systems (TCS). Many bacteria respond to the oxygen fluctuations via TCS. In the present work, a previously uncharacterized TCS, Bas1213-1214, of B. anthracis with a probable role in oxygen sensing has been characterized as a functional TCS. A substantial increase in the expression of Bas1213 was observed during the stationary growth phase, in presence of bicarbonate ions, and under oxidative stress thereby speculating the role of Bas1213 in toxin production and adaptive responses. Electrophoretic mobility shift assay (EMSA) and ANS assay highlighted autoregulation of the system. Identification of Bas1213 regulon further suggested its regulatory function in metabolism and adaptive responses. A marked reduction in sporulation was observed on overexpression of Bas1213 in B. anthracis which can be correlated with the augmented expression of sporulation kinase D. Additionally, Bas1213 was shown to regulate catalase, and ABC transporter (mntH) further implicating its essential role during oxidative stress. Finally, crucial residues involved in the DNA binding activity of Bas1213 were also identified. This study reports that the role of Bas1213-1214 in the regulation of metabolism and adaptive responses during oxidative stress. Both sporulation and response to environmental oxygen are important for the maintenance of B. anthracis lifecycle, therefore, characterization of Bas1213-1214 provides a step closer toward understanding the regulatory network governing in B. anthracis.
微生物定植是其基因表达适当感知和调节的结果。炭疽芽孢杆菌通过复杂的调控机制，包括双组分系统（TCS），来适应和在其环境中茁壮成长。许多细菌通过 TCS 对氧气波动做出反应。在本工作中，我们对炭疽芽孢杆菌中以前未表征的 TCS Bas1213-1214 进行了表征，该 TCS 可能在氧气感应中发挥作用，是一个功能性 TCS。在静止生长阶段、存在碳酸氢根离子和氧化应激下，观察到 Bas1213 的表达大量增加，推测 Bas1213 在毒素产生和适应性反应中发挥作用。电泳迁移率变动分析（EMSA）和 ANS 分析强调了该系统的自动调节。Bas1213 调控子的鉴定进一步表明了其在代谢和适应性反应中的调节功能。在炭疽芽孢杆菌中过表达 Bas1213 时，观察到明显的孢子形成减少，这与孢子形成激酶 D 的表达增加有关。此外，Bas1213 被证明调节过氧化氢酶和 ABC 转运体（mntH），进一步表明其在氧化应激期间的重要作用。最后，还确定了参与 Bas1213 DNA 结合活性的关键残基。本研究报告了 Bas1213-1214 在氧化应激期间调节代谢和适应性反应的作用。孢子形成和对环境氧气的反应对炭疽芽孢杆菌生命周期的维持都很重要，因此，Bas1213-1214 的特征提供了更接近理解炭疽芽孢杆菌调控网络的一步。
