Figure 6.

Plakoglobin is not required for the formation of actin-rich contractile rings during cytokinesis. (A and B) The first cleavage furrow of an uninjected embryo (A), and an embryo depleted using 4 ng of plakoglobin oligo (B). The vitelline membranes were manually removed immediately before the first cleavage division, and the cleavage furrow allowed to form before fixation and staining with Alexa 488–coupled phalloidin. In the depleted embryo, the weight of the egg contents in the absence of the elastic vitelline membrane pulls apart the contractile ring of actin. However, inside the vitelline membranes, these eggs go on to cleave normally.