Figure 1. Embryos undergo germ plasm RNP recruitment to furrows during the first three cleavage cycles. WT embryos fixed during furrow initiation for the first (A), second (D) and third (G) cleavage cycles. Recruitment was measured by averaging counts of RNPs found in each furrow for the 1st (B), 2nd (E), and 3rd (H) cell cycles during furrow initiation. RNP distal compaction was observed in mature furrows for the 1st (C), 2nd (F), and 3rd (I) cleavage cycles. Anti-p-NMII (green in A,D,G, grayscale in B,C,E,F,H,I) labels RNPs and anti-α-tubulin (red in A,D,G) labels microtubules. Panels in grayscale correspond to representative high magnification images corresponding to furrow initiation (B,E,H, to show RNP furrow recruitment, at stages similar to those in overviews in A,D,G, respectively) and furrow compaction (C,F,I, to show distal compaction at a slightly later stage in furrow maturation during the same cell cycle). Scale bars: 100 μM (A,D,G) and 10 μM (B,C,E,F,H,I)