Figure 6.

Simultaneous inhibition of centralspindlin and the CPC does not affect the initial recruitment of contractile ring proteins to the equatorial cortex. (A) The schematic highlights the first step in cytokinesis (boxed area), formation of the equatorial band. (B) A schematic of the method used to analyze formation of the equatorial band in D and F (Lewellyn et al., 2010). Spinning disk confocal optics were used to collect a 4 × 1–µm z series containing the embryo cortex every 20 s, and a maximum intensity projection was generated for each time point. A 50-pixel-wide line (approximately half the embryo width) was drawn across the projection, and embryos were divided into 20 equal length segments from anterior (0%) to posterior (100%). The mean GFP:anillin^ANI-1 or NMY-2:GFP in each segment, after subtraction of a background measurement for that segment made just before anaphase onset (120–160 s after NEBD; before detectable accumulation at the equator), was calculated for each time point. (C and E) Maximum intensity projections of the cortex in control and zen-4 & air-2(RNAi) embryos expressing GFP:anillin^ANI-1 (C) or NMY-2:GFP (E). (D and F) The mean postanaphase accumulation of cortical GFP:anillin^ANI-1 and NMY-2:GFP was quantified as a function of embryo length at the indicated time points after NEBD. The values for each dataset were normalized by dividing all intensity values by the mean value for controls (55–65% embryo length) imaged in parallel at the time point when band formation was maximal. Error bars are SEM. Bars, 10 µm.