TCF/Lef:H2B-GFP reporter transgene expression in E8.5 and E9.5 embryos. (A) Laser scanning confocal image of an 8-somite embryo and sections through it showing expression in the neural crest cells (A1, A2), the neural tube (A3, A4) and the presomitic and node region (A5, A6). (B) Widefield fluorescent image of a 23-somite stage embryo. Transverse sections reveal transgene expression in the brain (B1), the neural crest cells (B2), otic vesicle (B3), heart (B4), somites, neural tube (B5) and tail bud (B6). Aproximate planes of section are depicted by dashed lines. AVC, atrioventricular canal; hb, hindbrain; NCC, neural crest cells; nt, neural tube; ov, otic vesicle; PSM, presomitic mesoderm; so, somite; tb, tail bud.