Changes to PM morphology over the cell cycle. (A) Z-sections of PIP₂–positive PM from nuclear cycle 11–12. The yellow bracket shows a prometaphase compartment. Pink arrows show apical surface tubules at prometaphase. Orange arrows show PM folds at the apical periphery of prometaphase compartments, over the full surface of metaphase compartments, and restricted to the poles of telophase compartments. Purple arrows show PM tubules beneath PM folds at telophase. Corner brackets show a nascent cap at telophase. (B) Higher time resolution imaging of PIP₂–positive PM from telophase 11 to prometaphase 12. 1.5 µm projections of the apical surface show movement of a PM fold (yellow arrows) to the periphery of forming compartment (purple dots and yellow bracket). Z-sections show apically directed regression of PM tubules over the same time (red, green, and blue arrows show example tubules). The features described in A and B were seen in 5/5 embryos.