Fig. 1.

Principle of the CreER^T2/loxP system and schematic representation of commonly used fluorescent reporter constructs. a In the absence of Tamoxifen, CreER^T2 cannot efficiently enter the nucleus and thus will not recombine target genes. Tamoxifen administration causes CreER^T2 translocation to the nucleus and results in target gene recombination. In the case of the depicted reporter, excision of the loxP flanked stop codon leads to expression of the downstream-located fluorescent reporter gene. b Schematic representation of R26R-EYFP, mTmG, Ai13 and Ai14 reporter lines. LoxP sequences are depicted by triangles. neo^R: neomycin resistance, stop: stop codon, CAG: CAG promoter, WPRE (posttranscriptional regulatory element). The distance in between the loxP sites is indicated for each line (in kb)