Engineering more stable, selectable marker-free autoluminescent mycobacteria by one step

Area of Science:

• Microbiology
• Molecular Biology
• Drug Discovery

Background:

• Autoluminescent Mycobacterium tuberculosis reporter strains offer efficient evaluation of tuberculosis drugs and vaccines in vivo.
• Previous strains exhibited instability and reporter loss without selection.
• Kanamycin selection markers limited utility for tuberculosis drug screening and combination therapy evaluation due to resistance to essential drugs.

Purpose of the Study:

• To develop selectable marker-free and more stable autoluminescent mycobacterial reporter strains.
• To overcome limitations associated with selection markers in mycobacterial genetic manipulation.
• To create versatile reporter strains for diverse applications in tuberculosis research.

Main Methods:

• Utilized an integrative vector strategy for strain construction.
• Employed Xer site-specific recombination to remove resistance marker and integrase genes in a single step.
• Developed corresponding plasmid vectors for constructing other marker-free reporter strains.

Main Results:

• Successfully created stable, autoluminescent mycobacterial strains lacking selectable markers.
• Demonstrated the removal of resistance marker and integrase genes via Xer recombination.
• Developed convenient plasmid vectors for generating diverse marker-free reporter mycobacteria.

Conclusions:

• The developed selectable marker-free strains offer enhanced stability and broader utility for tuberculosis research.
• The integrative vector and Xer recombination strategy provides an efficient method for creating marker-free mycobacteria.
• The plasmid vectors are valuable tools for constructing novel reporter strains with various applications.