Using the brain to screen cloned genes

Expression-cloning systems, such as lambda gt11, are useful for isolating complementary DNAs (cDNAs) encoding proteins made in the nervous system. By using antibodies to screen expression libraries, even rare brain cDNAs can be detected. However, authenticating a cloned cDNA is often a major obstacle for further characterization. This article describes a strategy for confirming cDNAs that takes advantage of the anatomical distribution of the encoded protein within the brain. The approach is discussed in the context of cloning a neuropeptide cDNA, but is applicable to other proteins whose anatomical localization is known.