Prolonged ncdz treatment reveals complex gating of cortical pRLC levels. Medial single-section confocal images of S. purpuratus zygotes, from one female, fertilized synchronously, cultured to the stage shown, and immersed in 20 μM ncdz for the period indicated, then identically fixed and stained to reveal pRLC (lavender) and DNA (green). Identical microscope settings were used throughout for pRLC, but laser intensity was adjusted for different DNA condensation states. The number in each panel indicates chronological age (11.5°C) defined by the interval between sperm addition and the moment when that cell was transferred into fixative (e.g., 1:35 means fixed 1 h, 35 min after fertilization). The left column (0 min in 20 μM ncdz) shows the normal progression of control cells developing without ncdz. Each row displays cells that have spent 5, 10, and 20 min in ncdz, having been transferred into ncdz at the same time the control cells in the same row were transferred into fixation medium. Each panel shows one example of the most abundant phenotype for the specified time point, typically the only phenotype, determined by examining a slide containing >100 cells for the time point in question. Bar, 25 μm.