dio lox sites

Dio lox sites are double inverted orientation lox sites. This is a mechanism used by neurobiologists to insert different genes intot the brain of model organisms. The lox sites surround a gene that you want to insert. The gene is in nonsense orientation, meaning it will not be expressed unless it is in the presence of CRE recombinase which is able to flip the gene in certain circumstances. If there are dio lox sites (in the presence of CRE recombinase), then this is a two step process to perminantly flip the transgene into the sense direction to be expressed. The first step is one set of lox sites are brought togehter by the CRE recombinase. One of the lox sites the CRE is acting on will be inserted to the other side of the transgene and the transgene will be flipped. This leaves three lox sites on one side of the transgene, and one lox site on the other side. Of the tree lox sites on one side, two are in a pair and facing the same direction. These lox site pairs, in the presense of CRE will be spliced out of the gene sequence. The splicing of the lox sites from the gene sequence leaves two lox sites from different pairs in each sequence of DNA (one splices, and one with the transgene). Ultimately, this is a perminant change to the DNA because lox sites from different pairs cannot work together, the CRE will not recognize them as a pair. Therefore, the perminant flip will allow for the expression of the transgene in the cells that express CRE recombinase.