A pink mouse reports the switch from red to green fluorescence upon Cre-mediated recombination.
BACKGROUND
Targeted genetic modification in the mouse becomes increasingly important in biomedical and basic science. This goal is most often achieved by use of the Cre/loxP system and numerous Cre-driver mouse lines are currently generated. Their initial characterization requires reporter mouse lines to study the in vivo spatiotemporal activity of Cre.


RESULTS
Here, we report a dual fluorescence reporter mouse line, which switches expression from the red fluorescent protein mCherry to eGFP after Cre-mediated recombination. Both fluorescent proteins are expressed from the ubiquitously active and strong CAGGS promoter. Among the founders, we noticed a pink mouse line, expressing high levels of the red fluorescent protein mCherry throughout the entire body. Presence of mCherry in the living animal as well as in almost all organs was clearly visible without optical equipment. Upon Cre-activity, mCherry expression was switched to eGFP, demonstrating functionality of this reporter mouse line.


CONCLUSIONS
The pink mouse presented here is an attractive novel reporter line for fluorescence-based monitoring of Cre-activity. The high expression of mCherry, which is visible to the naked eye, facilitates breeding and crossing, as no genotyping is required to identify mice carrying the reporter allele. The presence of two fluorescent proteins allows in vivo monitoring of recombined and non-recombined cells. Finally, the pink mouse is an eye-catching animal model to demonstrate the power of transgenic techniques in teaching courses.
Department of Neurogenetics, Institute of Biology and Environmental Sciences, Carl von Ossietzky University, Oldenburg, Germany.
Heiner
H
Hartwich
Somisetty V
SV
Satheesh
Hans Gerd
HG
Nothwang
D000818:Animals; D003116:Color; D003118:Color Perception; D018703:Founder Effect; D018628:Gene Dosage; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D005838:Genotype; D049452:Green Fluorescent Proteins / Q000096:biosynthesis* / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D019426:Integrases / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D010641:Phenotype; D011401:Promoter Regions, Genetic; D011995:Recombination, Genetic; D012867:Skin / Q000378:metabolism; D014162:Transfection; D000097573:Red Fluorescent Protein
D049452:Green Fluorescent Proteins; D019426:Integrases; D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein; C485184:enhanced green fluorescent protein; C045073:Cre recombinase