Characterization of a two component system, Bas1213-1214, important for oxidative stress in Bacillus anthracis

Area of Science:

• Microbiology
• Bacterial Physiology
• Gene Regulation

Background:

• Bacillus anthracis adapts to its environment via complex regulatory mechanisms, including two-component systems (TCS).
• TCS are known to mediate bacterial responses to environmental cues like oxygen fluctuations.

Purpose of the Study:

• To characterize the previously uncharacterized TCS, Bas1213-1214, in B. anthracis.
• To investigate the role of Bas1213-1214 in oxygen sensing, metabolism, and adaptive responses.

Main Methods:

• Gene expression analysis under various conditions (stationary phase, bicarbonate, oxidative stress).
• Electrophoretic mobility shift assay (EMSA) and ANS assay to study autoregulation.
• Identification of the Bas1213 regulon.
• Overexpression studies to assess effects on sporulation and gene regulation (e.g., sporulation kinase D, catalase, mntH).
• Identification of DNA-binding residues.

Main Results:

• Bas1213-1214 was confirmed as a functional TCS involved in oxygen sensing.
• Bas1213 expression increased under stationary phase, bicarbonate, and oxidative stress.
• The system regulates metabolism, adaptive responses, and toxin production.
• Overexpression of Bas1213 reduced sporulation and increased sporulation kinase D expression.
• Bas1213 regulates catalase and mntH, essential for oxidative stress response.
• Key DNA-binding residues of Bas1213 were identified.

Conclusions:

• Bas1213-1214 plays a critical role in regulating B. anthracis metabolism and adaptive responses, particularly during oxidative stress.
• Understanding this TCS provides insights into the B. anthracis lifecycle, including sporulation and environmental oxygen response.