What is the lac operon and Emx1/Cre?
An operon is a unit of prokaryotic gene expression which includes co-ordinately regulated structural genes and control elements which are recognized by regulatory gene products. The Lac operon is the operon that regulates lactose metablism in E. Coli bacteria. The lac operon (lactose operon) has 3 structural genes, lacZ (which codes for beta-galactosidase – responsible for hydrolysis of lactose to galactose to glucose), lacY (which codes for a galactoside permease which transports lactose across cell wall) and lacA (codes for thiogalactoside transacetylase). These 3 structural genes are in a single transcription unit, lacZYA and have a single promoter, Plac. The 3 proteins are therefore expressed together. EMx1/Cre is a mouse homologue of the drosophila homeobox gene; it’s expression is limited to the neurons in a developing adult and adult cerebral cortex and hippocampus. Basically, (in gene knockouts of transgenic mice), the Cre gene is placed downstream from the EMx1 promoter. (in t
