Cell-Sized confinement in microspheres accelerates the reaction of gene expression

Area of Science:

• Biochemistry
• Cell Biology
• Synthetic Biology

Background:

• Understanding how cellular components interact within confined environments is crucial for deciphering biological processes.
• Lipid membranes play a vital role in compartmentalization and regulating biochemical reactions within living cells.

Purpose of the Study:

• To investigate the impact of lipid membranes on gene expression within cell-sized compartments.
• To quantify the effect of confinement and membrane properties on protein synthesis rates.

Main Methods:

• Utilized cell-sized water-in-oil droplets encapsulated by a lipid layer.
• Incorporated a cell-free translation system to synthesize green fluorescent protein (GFP).
• Measured GFP production rates (V(GFP)) and analyzed kinetics and dependence on droplet radius (R) and lipid composition.

Main Results:

• Observed a remarkable acceleration of gene expression, with GFP production rates remaining constant for approximately one day (0th-order kinetics).
• Found that V(GFP) was inversely proportional to droplet radius (R) for R < 50 μm, with a >10-fold increase in droplets with R ∼ 10 μm compared to bulk.
• Demonstrated that acceleration rates were highly dependent on the specific types of lipids used in the membrane.

Conclusions:

• The lipid membrane surface significantly facilitates protein production in cell-sized confined systems.
• The scale of confinement, particularly at the cellular level, amplifies the membrane's effect on biochemical reactions.
• This study highlights the importance of membrane-biochemical system interactions for efficient protein synthesis in engineered cellular environments.