Fig. 8.

S-phase cells derived from the main regions of cell proliferation do not contribute to the formation of new structures. A Schematic of the EdU pulse-chase experiments and PH3 immunostaining in regenerating cydippids after oral-aboral bisection and apical organ amputation. B–C” Confocal stack projections of bisected cydippids through the oral-aboral axis oriented in a lateral view showing the cut site in the first plane. D–E” Confocal stack projections of cydippids in which the apical organ was amputated oriented in an aboral view. The labeling corresponding to each panel is listed at the top of the columns, and the time of chase is listed to the left of the rows. Nuclei of S-phase cells are labeled with EdU (magenta), M-phase cells are stained with anti-PH3 (green), and all nuclei are counterstained with DAPI (blue). Dotted line rectangles in B, C, D, and E show the area corresponding to higher magnifications on the right. The pattern of EdU and PH3 staining is shown in cartoons on the left. Scale bars = 100 μm. Abbreviations: hab hours after bisection, hpa hours post amputation, tb tentacle bulb