Fig. 3

Over-expression of different deltas promotes hypochord cell fates over notochord at distinct positions along the anterior–posterior axis. (A–J) DIC and fluorescent in situ images of embryos with notochord to hypochord conversions at different positions along the anterior–posterior axis. DIC images are at 24 somites, while in situ images are at 24 hpf. ntl expression (red) marks the notochord, while αcol2a (green) shows the floor plate and hypochord. Embryos lacking notochord entirely are present, but have a twisted body axis and cannot be imaged easily via fluorescence, hence a weaker phenotype with some residual ntl expression is shown in (H). (K–M) Embryos at the 24 somite stage stained for αcol2a. Injection of some delta mRNAs can rescue hypochord formation in embryos where both deltaC and deltaD function have been impaired (i.e. deltaC^-/- embryos injected with a deltaD morpholino). Select hypochord cells are marked by arrows or brackets.