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/).

STAT3 accelerates uterine epithelial regeneration in a mouse model of decellularized uterine matrix transplantation

“…Since Rosa26 Cre-reporter knockin (R26GRR) mice exhibit green emission before and red emission after Cre-mediated recombination (7), and since Amhr2-Cre mice have specific expression of Cre recombinase in the stroma and myometrium (8), we generated R26GRR/ Amhr2-Cre mice, which have stroma/myometrium-specific red fluorescence of tdsRed in the uterus, to identify cell lineage of DMT. We transplanted the DUMs from WT donor mice into R26GRR/ Amhr2-Cre recipient mice.…”

“…WT ICR mice (Japan SLC), R26GRR mice (7), Ltf-iCre mice (66), Amhr2-Cre mice (8), Pgr-Cre mice (67), and Stat3 -floxed mice (68) (Oriental Bio Service) were used in this study. R26GRR mice exhibit green emission before and red emission after Cre-mediated recombination.…”

Dullard deficiency causes hemorrhage in the adult ovarian follicles

“…The Col1a1‐Cre mice used in Figures c and , which are identical to Col1a1‐Cre mice (Dacquin et al., ), were obtained from RIKEN BRC through the National Bio‐Resource Project of the MEXT, Japan, under accession number RBRC05603. R26GRR mice were obtained from Laboratory Animal Resource Center, University of Tsukuba (Hasegawa et al., ). Col1a1‐Cre ; Dullard flox/flox male mice (designated as Dullard Col1KO ) were mated with Dullard flox/flox female mice to generate Dullard Col1KO mice for experiments.…”

Finding degrees of separation: Experimental approaches for astroglial and oligodendroglial cell isolation and genetic targeting

“…These fluorescent reporters express either red fluorescent protein or green fluorescent protein before recombination, and then either green fluorescent or red fluorescence respectively, after recombination (De Gasperi et al, 2008; Hasegawa et al, 2013). The interesting discovery of a pink mouse among colonies of another newly established strain expressing mCherry/EGFP dual reporters, further adds convenience during animal husbandry with the strong emission of mCherry that is visible to the naked eye (Hartwich et al, 2012).…”