Phage display

Phage display is a test to screen for protein interactions by integrating multiple genes from a gene bank into phage.

Like the two-hybrid system, phage display is used for the high-throughput screening of protein interactions. The principle of this method is summarized as follows :

A phage will target another phagemid and insert its DNA between the signal and the native DNA, the result of this foreign DNA causes the phagemid to secrete a specific amino acid sequence coding for the foreign DNA.
 * 1) The function of protein X is unknown. The protein is used to coat the surface of a small plastic dish.
 * 2) Numerous genes, often all the genes in an organism's genome, are expressed in a library as fusions with the coat protein of a bacteriophage, so that they are displayed on the surface of the viral particle.
 * 3) This phage-display library is added to the dish. After a while, the dish is washed.
 * 4) Phage-displaying proteins that interact with protein X remain attached to the dish, while all others are washed away. DNA extracted from interacting phage contains the sequences of interacting proteins.

Phage display is also a widely used method for in vitro protein evolution (also called protein engineering). Competing methods for in vitro protein evolution are yeast display, bacterial display, ribosome display, and mRNA display.