Files in this Data Supplement:
Fig. S1. Detection of endosomes in macromeres and micromeres during the fifth cell cycle. (A,B) Example image before (A) and after (B) endosome detection. Rhodamine dextran-positive endosomes were detected using pixel thresholding and filtered for spots above 0.1 µm2. The results of the detection are shown in B and all detected spots are shown with a pseudocolor. DNA is stained with by Hoechst 33342. Scale bar: 10 µm. (C,D) Average number (±s.e.m.) of endosomes measured in micromeres (solid lines) and macromeres (broken lines) using rhodamine dextran (n=3×5×4, batches × embryos × cells from each embryo), a marker of fluid-phase endocytosis, and cholera toxin B (n=3×5×4), a marker of the ganglioside GM1, which is found in lipid rafts.
Fig. S2. Fumitremorgin C does not inhibit mitoxantrone accumulation. Equatorial confocal sections through eight-cell embryos that have accumulated mitoxantrone with and without exposure to 5 µM Fumitremorgin C, an ABCG2 inhibitor. This shows that there is little fumitremorgin C-inhibitable accumulation of mitoxantrone. Scale bars: 10 µm.
Movie 1. Micromeres and small micromeres accumulate calcein at an accelerated rate. Live time-lapse confocal microscopy of S. purpuratus early cleavage embryos exposed to calcein-AM at the two-cell stage. Fourteen 2.79 µm z-sections were taken through 36 µm of the embryos every 4 minutes. Time-lapse movie is a compilation of MIPs over time made using Volocity imaging software.