IPTG is a compound that induces transcription of the lac operon by mimicking allolactose, a lactose metabolite. IPTG is routinely used as a tool in cloning and gene recombination to confirm successful gene insertion.
| Mechanism of Action | IPTG induces the lac operon by binding to and releasing the lac repressor allowing transcription of lac genes including beta-galactosidase. |
| Microbiology Applications | IPTG can be used to confirm successful DNA recombination within the lac operon in cloning experiments. X-gal, a chromogenic substrate which turns a blue color when cleaved by IPTG can be used in the media in which the cells are grown. White colonies indicate a gene insertion within the lac operon because beta-galactosidase was not expressed. Blue colonies are indicative of an intact lac operon which expressed beta-galactosidase and subsequently cleaved X-gal. |
| References | Chang, Lewis M., and N. C. Horton. "Crystal Structure of the Lactose Operon Repressor and Its Complexes with DNA and Inducer." Europe PubMed Central 271.5253 (1996): 1247-254. Europepmc.org. Web. 4 Dec. 2012. |
