Protein Synthesis in Cell-Free Systems

Abstract

Cell-free extracts are widely used to identify and study the proteins encoded by cloned cDNAs, viral genomes or other exogenous mRNA, etc., as well as to investigate transcriptional and translational control. In vitro translation is in many instances the method of choice for the rapid analysis of uncharacterized proteins, provided that the cDNA encoding for the protein is available. It has been demonstrated that the in vitro translated protein can be used for immunoanalysis (immunoblotting, immunoprecipitation etc.), for functional activity tests of the product, for studying proteolytic processing and so on. If a purification tag is fused to the cDNA of the protein, the synthesized product can be directly purified from the in vitro translation mix and used for subsequent studies. Commercially available in vitro translation extracts also allow the co-translation of several different proteins simultaneously, thus providing a system to study protein:protein interactions as well as protein:DNA and protein: RNA interactions.