Wnt reporters in animals

There are various "reporter transgenes" that respond to Wnt signals in intact animals and therefore, as far as one can know, reflect endogenous Wnt signaling (reviewed in Barolo, 2006). These reporters are based on a multimerized TCF binding site, driving expression of LacZ or GFP. Other lines allow for lineage tracing of Wnt responding cells, using the Cre/ERT2 gene inserted into Wnt target genes. 

Animal strain (linked to resource)

reporter

reference

TOP-GAL (obtain from Jackson Labs)
3 TCF sites, c-fos promoter, LacZGupta and Fuchs (1999
BAT-GALTCF sites, Siamois promoterMaretto et al (2003),  
 ins-TOPEGFP, ins-TOPGAL TCF sites, LacZ or GFP, insulator elementsMoriyama (2007) (mice not available anymore)
LEF-EGFP TCF sites, EGFP Currier et al, (2010). 
TCF/Lef:H2B-GFP reporter (obtain from Jackson labs)TCF sites, H2B-GFP, (Ferrer-Vaquer et al 2010
Axin2-LacZ  (obtain from Jackson Labs) 
Insert of LacZ into Axin2, Wnt target geneLustig et al, (2002) 
Axin2-d2EGFP  
Axin2 promoter, EGFP Jho et al, (2002),  
Lgr5tm1(cre/ERT2) (obtain from Jackson Labs)   
Cre/ERT2 insert into LGR5, Wnt target geneBarker et al (2007)
Axin2-Cre/ERT2 (obtain from Jackson Labs)   Cre/ERT2 insert into Axin2, Wnt target geneVan Amerongen (2012)
Tcf3-CreER Cre/ERT2 into TCF3Howard et al, (2014)
TOPdGFP ZebrafishTCF sites, dGFPDorsky and Moon (2002)
Tcf/Lef-miniP:dGFP ZebrafishTCF sites, dGFPShimizu et al, 2012

Movie: Expression of Tcf/Lef-miniP:dGFP in the Zebrafish embryo. From Shimizu et al, 2012

 

In response to the often-asked question "what is the best Wnt reporter", there is no simple answer. In our experience, Axin2/Conductin is widely expressed in areas where one would expect it, and might be an optimal reporter for many tissues. However, there are cells (in the lung for example) that are positive for the TOP-GAL reporter and negative for Axin2-based reporters (Al Alam et al, 2011). The problem of reliably detecting Wnt signaling in vivo is compounded by difficulties in assessing Wnt gene expression itself (which is best done by in situ hybridization as antibodies are rarely good enough), or in finding other independent hallmarks of Wnt signaling (see Barolo, 2006 and Al Alam et al, 2011).