Fig. 5

The cell state splitter is an organelle predicted [9] and then at first observed at the apical end of ectoderm cells in axolotl embryos at early gastrulation [11]. It consists of an upper microfilament ring with an intermediate filament ring below it, subtended by a mat of microtubules. As shown in the thumbnail in the upper right, the cell state splitter occupies only 1 % of the height of an ectoderm cell. (Below and in the thumbnail, the vertical and horizontal scales are compressed, as 50 μm = 100 × 0.5 μm)