Differential display competitive polymerase chain reaction: An optimal tool for assaying gene expression

Gene discovery, i.e. detection of genes whose expression is affected in dis eases or by different treatments of cells or animals, has become the focus of much genetic research. The technologies that are used to detect changes in expression level include polymerase chain reaction (PCR)-based subtracti on methods, arrays of cDNA clones on chips or filters, serial analysis of g ene expression, and differential display. In this paper we show that differ ential display can be used to investigate global gene expression in situati ons where a few genes change expression levels such as exposure of MCF7 cel ls to estradiol, and in more complex situations such as neuronal differenti ation of human NTERA2 cells which affects a large number of genes. Furtherm ore, we show that differential display can replace Northern blotting and RN ase protection as a tool to study the expression level of a specific gene i n many samples. Results obtained by differential display can be stored in d atabases, where the identity of a band (gene or mRNA name) can be linked wi th information about the primer combination displaying the band and a gel i mage showing the band pattern, which is all the information that is needed to compare the expression level of this gene in other samples.