Fig. 5. Dll4 inhibits V2a lineage progression. Chick embryos were electroporated with human DLL4 (hDll4) in the form of hDll4-Myc at st14-16 and analysed after 48 hours. (A-B) Double immunolabelling for Chx10 (red) and hDll4-Myc (green) showing repression of Chx10-positive cells. (B) Quantification of Chx10-labelled cells showed a 50% decrease on the hDll4-electroporated side compared with the contralateral, control side. (C) Some hDll4-electroporated cells co-express Chx10, consistent with the idea that Dll4 can suppress V2a generation in a non-cell-autonomous fashion. (D) Immunolabelling for hDll4-Myc (green). (D') Dll4 exceptionally can induce Gata2 (arrowhead). (D'') Dll4 does not affect Scl expression. (E) Dll4 does not greatly affect generation of V2b INs, judging by ISH. Quantification of V2b markers Gata2 and Scl by pixel-counting software showed no significant effect on V2b production (see text for statistics).