Targeted Regulation of Protein Expression in Vibrio parahaemolyticus

Area of Science:

• Microbiology
• Molecular Biology
• Bacterial Pathogenesis

Background:

• *Vibrio parahaemolyticus* possesses virulence factors like TDH, TRH, and type III secretion systems (T3SSs).
• T3SS1, particularly its effector VP1680, is crucial for cytotoxicity.
• Understanding the link between effector expression, quantity, and cytotoxicity requires precise control systems.

Purpose of the Study:

• To develop a system for regulating effector protein expression timing and levels in *V. parahaemolyticus*.
• To establish a targeted protein degradation system for controlling intracellular protein abundance.
• To investigate the quantitative relationship between effector protein levels and bacterial cytotoxicity.

Main Methods:

• Developed an arabinose-dependent transcription factor system to control VP1680 expression.
• Established ssrA-tagged protein degradation using ClpP/ClpX or ClpP/ClpA systems.
• Combined expression and degradation systems for dynamic protein level control.

Main Results:

• VP1680-dependent cytotoxicity increased with controlled expression.
• Achieved >50% degradation of tagged proteins within 20 minutes.
• Generated a highly fluorescent enhanced green fluorescent protein variant in *V. parahaemolyticus*.

Conclusions:

• The developed systems enable precise control over intracellular protein levels.
• Facilitates detailed examination of protein quantity-phenotype relationships, moving beyond the "all-or-nothing" model.
• Offers potential for studying bacterial virulence mechanisms and developing new control strategies.