Fig. 11. Enlarged myotomes of lbx1-injected tadpoles is not the result of recruitment of non-myogenic lineages. (A,B) Injection of myoD (A) or myoD + lbx1 (B) mRNA does not cause an increase in cell proliferation on the injected side (right side), as judged by pH3 staining on transverse sections of stage 29 tadpoles. Instead, non-myogenic lineages such as the pronephros are recruited to the myotome. (C,D) Transverse sections through stage 31 tadpoles indicate that both NCAM staining in the neural tube (C, arrow) and Pax8 staining in the pronephric tubules (D, arrow) are present on the injected side. (E,F) Lateral views of a tadpole injected with lbx1 show the presence of pronephric tubules on both the uninjected (E) and injected (F) sides (arrows). (G-J) Stage 31 tadpoles injected with myoD alone (G,H) or myoD + lbx1 (I,J), and stained with pax8, show normal pronephric tubules on the uninjected sides (G,I, arrows), but are lacking on the injected sides (H,J). However, tadpoles injected with lbx1 alone do not show a lack of tissues surrounding the myotome, despite there being a larger somite.