Gal4/UAS expression system-dependent gene recombination and cell imaging mice

RIKEN BRC February 2023
Mouse of the Month
Gal4/UAS expression system-dependent
gene recombination and cell imaging mice

Crl:CD1(ICR)-Tg(UAS-cre/T2A/miRFP670)216Staka (RBRC11716)


The schematic strategy of Notch1 signaling visualization is shown in the upper panel. Notch1 signaling induces the expression of both Cre recombinase and miRFP670 (ongoing Notch1 signaling). In combination with R26GRR strain (RBRC04874), Cre recombinase marks past Notch1 signaling with tDsRed expression. The neural tissues including the hippocampus and retina receive Notch1 signaling during their development. The lower images show the past and ongoing Notch1 signaling in each tissue.


The Gal4/UAS expression system is an inducible gene expression system that utilizes binding of the yeast-derived transcription factor Gal4 and its enhancer sequence, UAS. This experimental system has been used in Drosophila and so on. The UC2i mouse (RBRC11716) is a UAS-Cre-T2A-miRFP670 transgenic mouse strain that expresses Cre recombinase and near-infrared fluorescent protein miRFP670 in a Gal4-dependent manner. By controlling Gal4 expression, both genetic recombination via Cre/loxP system and non-invasive in vivo imaging are possible. In fact, depositors (Dr. Takahashi and Dr. Yoshihara) and their colleagues carried out mating experiments with an UC2i strain, a Cre fluorescent reporter R26GRR strain (RBRC04874) and a transgenic strain expressing the Notch1 receptor with its intracellular domain replaced by Gal4. As a result of analysis, they found that in response to endogenous Notch1 ligand binding to modified Notch1 receptors, Gal4 was cleaved from the plasma membrane, resulting in expression of Cre recombinase and miRFP670. They also reported that fluorescence expression by Cre reporter and imaging by miRFP670 allowed visualization of ongoing and past Notch1 signaling at the cellular level.
In terms of cellular dynamics analysis, Cre recombinases and fluorescent proteins have been used for imaging transcription factor expression. In addition to these purpose, UC2i mice can visualize protein-protein interactions by combining with various Gal4-expressing strains. This strain will be applied in not only developmental biology but also a wide range of fields.


Keywords : Gal4/UAS, Cre/loxP, miRFP670、in vivo imaging, protein-protein interaction
Depositor : Satoru Takahashi, M.D., Ph.D. & Masaharu Yoshihara, M.D., Ph.D.
University of Tsukuba
Strain name : Crl:CD1(ICR)-Tg(UAS-cre/T2A/miRFP670)216Staka
RBRC No. : RBRC11716
Reference : Yoshihara M, Nishino T, Sambe N, Nayakama T, Radtke F, Mizuno S, Takahashi S.
Generation of a Gal4-dependent gene recombination and illuminating mouse.
Exp Anim. 2022 Aug 5;71(3):385-390.
Related strain : C57BL/6N-Gt(ROSA)26Sor<tm1(CAG-EGFP/DsRed)Utr>/Rbrc (RBRC04874)
Related archives : Mouse of the Month October 2018
Mouse of the Month March 2014


February 2023
Saori Mizuno, Ph.D.
Contact: Experimental Animal Division, RIKEN BioResource Research Center (
All materials contained on this site may not be reproduced, distributed, displayed, published or broadcast without the prior permission of the owner of that content.

Comments are closed.