Morphogenesis of NEM/forerunner cells from 65-80% epiboly.
End of NEM to forerunner cell transition.
This is a high magnification series of a dorsal view of the embryo. The embryo is oriented with animal pole toward the top. Embryo was double labeled with SYTO-11 (green) and BODIPY 564/591 (red) and imaged with dual channel confocal microscopy (green channel on left, red channel on right).
While most the NEM/forerunner cells are in the forerunner position in front of the margin, their are still some cell that have not completed this movement. Also notice the more stable cell-cell attachments of the most vegetal forerunner cells with YSL-EVL border. Other forerunner cells are actively crawling in the space between the EVL and YSL, while those near the EVL-YSL border have stable adhesions.