eMks interact with PDPN-expressing neuroepithelium. (A) Confocal microscopic image of single optical slice (left) and a 3-dimensoinal surface rendering (right) of an eMk within the lower diencephalon PNVP closely associated with PDPN⁺ neural tissue (arrows). (B) Pseudocolored TEM image of an eMk with lamellipodia (yellow arrows) and neuroepithelium (red arrows point to interaction with eMk) in an angiogenic sprout (green) in the lower diencephalon. NEC, neuroepithelial cell. EC, endothelial cell. (C) Confocal microcopy of eMks stained with the α-granule marker TSP-1 in the lower diencephalon. CD41 marks the eMks; arrows mark CD41⁺TSP-1⁻ ectoplasmic lamellipodia. (D) Representative bright-field microscopy of semithin sections of eMks and their lamellipodia (yellow arrows) in the PNVP (left image) and vascular sprouts in the neural tissue (right 2 images) of the diencephalon. Red arrows mark interactions of lamellipodia processes with neuroepithelium (NEC). The percentage of eMks interacting with NECs in the diencephalon is shown on the right. Data represent mean ± standard error of the mean; n, embryos with at least 20 eMks/embryos analyzed. Scale bars, 10 μm (A,C-D); and 2 μm (B). **P < .01.