A genetic screen for mutations affecting temperature sensing in Bacillus subtilis.

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Two-component systems, comprising receptor histidine kinases and response regulators, are essential for microbial cellular processes.
• DesK is a well-characterized thermosensor histidine kinase in Bacillus subtilis, regulating responses to temperature changes.
• Understanding the functional amino acids in DesK is critical for elucidating its thermosensing mechanism.

Purpose of the Study:

• To develop and implement a novel screening procedure for identifying amino acids essential for DesK histidine kinase function.
• To identify specific mutations affecting DesK's temperature-sensing capabilities.
• To establish a versatile reporter assay applicable to various bacterial signaling systems.

Main Methods:

• Random mutagenesis of the membrane sensor domain of the DesK coding sequence.
• A screening strategy utilizing changes in colony morphogenesis during Bacillus subtilis sporulation as a readout.
• Recovery and analysis of mutants exhibiting defects in DesK temperature sensing.

Main Results:

• Successfully identified amino acids critical for DesK thermosensor histidine kinase activity.
• The developed screening method enabled the isolation of mutants with impaired temperature sensing.
• Demonstrated the efficacy of the colony morphogenesis-based reporter assay for DesK function.

Conclusions:

• The novel screening procedure effectively identifies key amino acids for DesK thermosensor function.
• This methodology is adaptable for studying other histidine kinases in Bacillus subtilis and diverse bacterial species.
• The reporter assay platform holds potential for broader applications in analyzing transcriptionally regulated systems.