Gene expression in a cell-free system on the preparative scale

A cell-free system for preparative gene expression is described. It is composed of DNA-free Escherichia coli extract and added plasmid DNA; coupled transcription-translation proceeds with a continuous flow of the feeding solution containing nucleoside triphosphates and amino acids. The system works at a high constant rate for tens of hours. The yield of synthesised proteins after 20-50 h is hundreds of micrograms from 1 ml of the reaction mixture. Electrophoretic analysis of translation products confirms synthesis of proteins of the expected molecular mass.