Fig. 5. Inactivation of Cos2 function induces ectopic Hh signalling in the ventral neural tube. (A) fkd4 expression in the ventral neural tube (MFP and LFP cells) of a 22-somite stage wild-type embryo. (B) Upregulation of the levels and expansion in the domain of fkd4 expression in the ventral neural tube of a 22-somite stage cos2 morphant (n=16/22). (C) Expression pattern of fkd4 in ventral cell populations of the developing mid- and hindbrain of a 22-somite stage wild-type embryo. (D) Increased levels and enlargement of the domain of fkd4 in ventral cell populations of the developing mid- and hindbrain of a 22-somite stage cos2 morphant embryo (n=13/22).