Fig 7.

Brainbow. A. Strategy for creating Brainbow mice. In Brainbow 1.0 and Brainbow 1.1 excision of different fluorophores from incompatible lox variants generates 2 to 3 different color combinations of XFP. In 2.0 the XFP genes are placed head to head between two asymmetric loxP sites. Activation of recombination by CRE causes inversion and change in the expression of the fluorophore from red to cyan. Place the inverted fluorophore genes between asymmetric loxP sites in tandom increases the number of combinations to four. B. Fluorescent fluorophore expression in mouse hippocampus. Adapted with permission from ¹²⁸.