Peptide aptamers: dominant "genetic" agents for forward and reverse analysis of cellular processes

Peptide aptamers are the newest in the class of "genetic" agents that aid in the analysis of cellular processes. Peptide aptamers interact with and can inactivate gene products, but don't mutate the DNA that encodes them. Reverse analysis with peptide aptamers involves isolating aptamers that interact with a specific protein and monitoring the resulting aptamer-induced phenotype. Conversely, forward analysis with peptide aptamers involves expressing combinatorial libraries of aptamers within an organism and screening for aptamer-induced variations in their phenotypes. The two-hybrid system is used in both processes to help identify the protein interactions, and variations from the basic procedure as described in UNIT are presented here.