FIGURE 4. Combinatorial XFP expression results from tandem copy integration.
From the following article:
Transgenic strategies for combinatorial expression of fluorescent proteins in the nervous system
Jean Livet, Tamily A. Weissman, Hyuno Kang, Ryan W. Draft, Ju Lu, Robyn A. Bennis, Joshua R. Sanes & Jeff W. Lichtman
Nature 450, 56-62(1 November 2007)
doi:10.1038/nature06293
a, With a Brainbow construct expressing three XFPs, independent recombination of three transgene copies can, in principle, generate ten distinct colour combinations. b, Oculomotor axons of Thy1-Brainbow-1.0 line H (recombination with CreERT2). Boxes show sample regions from different axons. c, Dentate gyrus of Thy1-Brainbow-1.0 line L (recombination with CreERT2). d, A single FRT site inserted in Brainbow constructs allows tandem transgene copy number reduction through Flp-mediated recombination. The PCR indicates the disappearance of transgene repeats in Thy1-Brainbow-1.0 line H crossed with Flp-expressing mice (inset). e, A Flp-recombined line derived from line H expresses XFPs in a mutually exclusive manner. Scale bars, 10 
m.
