Fig. 5. Effects of unc-60A (RNAi) on early development. Developmental processes of the control or unc-60A (RNAi) embryos from pronuclear meeting (a-c) to the four-cell stage (m-o) were observed by time-lapse DIC microscopy. A control embryo is shown in a, d, g, j, m and Movie 1. A representative cytokinesis defect resulting from unc-60A (RNAi) is shown in b, e, h, k, n and Movie 2. A cleavage furrow appeared after nuclear division (h) but regressed before completing the cleavage (k, arrows). The attempts at cleavage continued and resulted in irregular compartmentalization (n). A representative patterning defect is shown in c, f, i, l, o and Movie 3. Spindle orientation was normal at the second division (l), but the subsequent positioning of the four blastomeres was abnormal (o) compared with the control embryo (m). Bar, 10 µm.