Production of Virus-like Particles in Engineered E. coli

Take a tube containing a starter culture of engineered E. coli cells, harboring the lac operator-regulated T7 polymerase gene along with an expression plasmid.

The plasmid carries a gene encoding a coat protein derived from bacteriophage Qβ.

This gene is regulated by a T7 promoter and lac operator.

Transfer the culture to a flask containing a medium.

Incubate with shaking to promote bacterial growth.

Add a synthetic analog of allolactose that inactivates the lac repressor, triggering T7 polymerase expression.

The T7 polymerase then binds to the T7 promoter on the plasmid and transcribes the coat protein gene, which is translated to produce the coat protein.

These coat proteins self-assemble into virus-like particles (VLPs) that form non-infectious scaffolds.

Transfer the culture to centrifuge bottles.

Centrifuge to pellet the cells.

Discard the supernatant and transfer the pellet to a tube.

The cell pellet, containing intracellular VLPs, is ready for purification.

Prior to starting the procedure for expressing the Q-Beta bacteriophage, wipe down the bench area with a 1:1 bleach: ethanol solution. In an aseptic environment, make two three-milliliter starter cultures by adding single colonies of