Fig. 4

Cytoplasmic F-actin is the major source of active diffusion. a Living control egg chambers or b egg chambers over-expressing the actin nucleator SpireB. Overexpression of SpireB causes an increase in the amount of F-actin in the oocyte (see also Supplementary Fig. 4). c, d spire mutant oocytes were incubated in control DMSO-containing medium (c) or in colchicine-containing medium d. As expected, spire mutants do not form an actin mesh. Scale bar is 30 µm