In vivo Wnt signaling tracing through a transgenic biosensor fish reveals novel activity domains

► TCF responsive elements linked to a fluorescent reporter reveal Wnt/b-catenin activity in a whole zebrafish. ► Wnt reporter (7xTCFsiam) fish unveils novel tissues of wnt/b-catenin dynamic expression. ► Wnt activity can be followed in vivo in embryonic, larval and adult sensory organs and brain endothelia. ► Wnt signaling is revealed in vivo in regenerating tissues. ► Wnt reporter fish can be used both for drug screenings and wnt mutants phenotyping.