Article

A Global double-fluorescent Cre reporter mouse

Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, USA.
genesis (Impact Factor: 2.02). 09/2007; 45(9):593-605. DOI: 10.1002/dvg.20335
Source: PubMed

ABSTRACT

The Cre/loxP system has been used extensively for conditional mutagenesis in mice. Reporters of Cre activity are important for defining the spatial and temporal extent of Cre-mediated recombination. Here we describe mT/mG, a double-fluorescent Cre reporter mouse that expresses membrane-targeted tandem dimer Tomato (mT) prior to Cre-mediated excision and membrane-targeted green fluorescent protein (mG) after excision. We show that reporter expression is nearly ubiquitous, allowing visualization of fluorescent markers in live and fixed samples of all tissues examined. We further demonstrate that mG labeling is Cre-dependent, complementary to mT at single cell resolution, and distinguishable by fluorescence-activated cell sorting. Both membrane-targeted markers outline cell morphology, highlight membrane structures, and permit visualization of fine cellular processes. In addition to serving as a global Cre reporter, the mT/mG mouse may also be used as a tool for lineage tracing, transplantation studies, and analysis of cell morphology in vivo.

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    • "To distinguish between possible b cell fates, we generated a mouse model with conditional deletion of Ins2 (Fan et al., 2009) on an Ins1-null background (Duvillié et al., 2002), where b cell selective tamoxifen-inducible Cre is driven by a Pdx1 promoter fragment (Pdx1Cre ERT ) (Figure 1B). This Cre ''deleter'' allele resulted in virtually complete recombination , as measured by the antibody staining against membrane targeted GFP from the mTmG reporter allele (Muzumdar et al., 2007) ($99%; Figure 1C). Acute Ins2 gene knockout resulted in the expected loss of circulating insulin and sustained diabetes in all experimental Ins1 À/À :Ins2 f/f :Pdx1Cre ERT :mTmG but not in control Ins1 À/À :Ins2 f/f :mTmG mice (Figure 1D). "
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