Depletion of Par-1 or Dia reduces cap growth. (A) Moe-ABD–GFP decorates the caps. For control mCherry RNAi, each cap grows centrifugally in the apical plane (one cap bracketed) and then bends inward, forming compartment furrows (green arrows). With par-1 or dia RNAi, caps initiate, but centrifugal growth (one cap bracketed) and furrows (green arrows) are reduced. Time = 0 is arbitrary. Genotypes begin at the same stage. (B) Cap area versus time for control, par-1, and dia RNAi cycle 11 embryos. Caps quantified every third time frame from initial appearance to their meeting with neighboring caps (see Materials and methods). Just before the meeting of neighboring control caps (207 s), cap areas were significantly larger for controls versus par-1 or dia RNAi (P < 0.01 for each comparison). Time given in minutes and seconds.