Protein microarray generation by in situ protein expression from template DNA

Today, whole genomes are analyzed by Next-Generation Sequencing systems, or displayed by DNA microarray in situ synthesis. However, genomic data are mainly static and do not exactly reveal the complexity of protein interaction networks of any organism or cell. To investigate protein interactions, the generation of protein microarrays, displaying whole proteomes is a prerequisite. But traditional protein microarray generation is time consuming, costly, and is restricted by a wide range of technical difficulties concerning cell culturing, protein purification, and transfer onto microarray. Some of these obstacles can be bypassed by application of cell-free expression systems, enabling fast in situ synthesis of protein microarrays without need for cell culturing. This review provides a historical timeline of the different methods to generate protein microarrays by cell-free expression, highlights differences and similarities, and reports the current state of the different approaches.