title: Novel ROSA26 Cre-reporter knock-in C57BL/6N mice exhibiting green emission before and red emission after Cre-mediated recombination.
abstract: The Cre/loxP system is a strategy for controlling temporal and/or spatial gene expression through genome alteration in mice. As successful Cre/loxP genome alteration depends on Cre-driver mice, Cre-reporter mice are essential for validation of Cre gene expression in vivo. In most Cre-reporter mouse strains, although the presence of reporter product indicates the expression of Cre recombinase, it has remained unclear whether a lack of reporter signal indicates either no Cre recombinase expression or insufficient reporter gene promoter activity. We produced a novel ROSA26 knock-in Cre-reporter C57BL/6N strain exhibiting green emission before and red after Cre-mediated recombination, designated as strain R26GRR. Ubiquitous green fluorescence and no red fluorescence were observed in R26GRR mice. To investigate the activation of tdsRed, EGFP-excised R26GRR, R26RR, mice were produced through the crossing of C57BL/6N mice with R26GRR/Ayu1-Cre F1 mice. R26RR mice showed extraordinarily strong red fluorescence in almost all tissues examined, suggesting ubiquitous activation of the second reporter in all tissues after Cre/loxP recombination. Moreover, endothelial cell lineage and pancreatic islet-specific expression of red fluorescence were detected in R26GRR/Tie2-Cre F1 mice and R26GRR /Ins1-Cre F1 mice, respectively. These results indicated that R26GRR mice are a useful novel Cre-reporter mouse strain. In addition, R26GRR mice with a pure C57BL/6N background represent a valuable source of green-to-red photoconvertible cells following Cre/loxP recombination for application in transplantation studies. The R26GRR mouse strain will be available from RIKEN BioResource Center (http://www.brc.riken.jp/lab/animal/en/).
authors.affiliation: Laborarory Animal Resource Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Daitoku
authors.forename: Keito
authors.initials: K
authors.lastname: Sekiguchi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Tanimoto
authors.forename: Saori
authors.initials: S
authors.lastname: Mizuno-Iijima
authors.forename: Seiya
authors.initials: S
authors.lastname: Mizuno
authors.forename: Noriko
authors.initials: N
authors.lastname: Kajiwara
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Ema
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Miwa
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Mekada
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshiki
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Sugiyama
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yagami
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D053595:Embryonic Stem Cells; D042783:Endothelial Cells / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D055879:Gene Knock-In Techniques; D017930:Genes, Reporter / Q000235:genetics* / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D019426:Integrases / Q000235:genetics* / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism; D008164:Luminescent Proteins; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011995:Recombination, Genetic; D054875:Ubiquitination; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D019426:Integrases; D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein; C045073:Cre recombinase