Movie 1

Tracking individual cell G1 and S/G2/M fates in a Fucci cell cycle reporter E11.5+12h molar placode by live tissue confocal imaging shows placode IK cells stay in G1 phase
Fluorescence confocal microscopy time-lapse of an embryonic mouse E11.5 whole-mount mandible explant imaged for 12h. Image stacks were taken at 20min intervals, and the playback speed here is five frames per second. The tracking of individual cell fates from the placode stage is shown as a surface rendering of the Fucci cell cycle indicator: the contribution of individual G1/G0 phase cells in the placode and initiation knot are shown color coded in red hues and S/G2/M cells in green. Individual cell divisions of mother cells and their daughters are color coded in blue, green and yellow shades, respectively. IK G1/G0 cells in the placode did not re-enter the cell cycle. In contrast neighboring cells, distally from the IK, frequently entered S/G2/M phase and cell divisions contributed to invagination locally.

The initiation knot is a signaling center required for molar tooth development

Isabel Mogollón, Jacqueline E. Moustakas-Verho, Minna Niittykoski, and Laura Ahtiainen

Development 2021. 148:None-None; doi: 10.1242/dev.194597