Dia and F-actin are both required for a bundle-like distribution of Par-1. (A) Control or dia RNAi in embryos expressing endogenous Par-1–GFP and stained with phalloidin and Dia antibodies. In control caps, Par-1–GFP at Dia-positive actin bundles (arrows). In dia RNAi caps, Par-1–GFP and F-actin were cortical but bundles were not detected, and Dia was minimally detected. Observed in 12/12 control embryos and 13/13 dia RNAi embryos at cycles 10 and 11. Images deconvolved (except for Dia staining). (B) Effects of Latrunculin A or carrier injection on endogenous Par-1–GFP in live embryos. Par-1–GFP–positive bundles (white arrows) were observed in carrier control caps, but not Latrunculin A caps. Par-1–GFP–positive centrosomes were observed in both cases (yellow arrows). Observed in 7/7 controls and 6/6 Latrunculin A–injected embryos at cycles 11 and 12.