Fig. 2.

TH controls bone and cartilage formation (A and D), muscle development (B and E), and DNA replication (C and F) in the limb. Premetamorphic NF 55 tadpoles were grown for 1 week in 1 mM methimazole. Then 10 nM T3 was added to the rearing water of one group of tadpoles (D–F) but not others (A–C) for 3 days. The hind limbs were fixed, and frontal sections were prepared for in situ hybridization (15). sox-9 (CF285736; A and D), alpha 1 skeletal muscle actin (BC046739; B and E), and cyclin D2 (CA792959; C and F) were used. (Scale bar: 200 μm.)