mpH-1 confers shortening of M rows and loss of M3. (A–O) SR-SIM images of a WT (A) and mpH-1 homozygote cells (B–O) grown at 30°C and immunostained with 20H5 anti-centrin (red) and DAPI (blue). In panels A–D, white arrows mark the M rows. (B–D)mpH-1 mutant cells in interphase. The cell in B has a highly reduced M3. The cells in C and D lack M3. (E–L)mpH-1 cells during divisional oral development. (E) Stage 1a. (F) Stage 1b. (G) Stage 2. (H) Stage 3. (I) Stage 4a. (J) Stage 5a. (K) Early stage 5f. (L) Late stage 5f. (M–O)mpH-1 cells that undergo OR. (M) Stage 1b. (N) Stage 2. (O) Stage 4a. (P) Quantification of the length of M1 row. Mean ± SD (3.6 ± 0.8 μm in the mpH-1 homozygotes and 6.19 ± 0.3 μm in the WT). N = 3 experiments (10 measurements per experiment). P < 0.0001 in a two-way ANOVA test with Geisser–Greenhouse correction for variability. oa, old oral apparatus in various stages of resorption during oral replacement; noa, new oral apparatus in cells undergoing OR.