Fig 1

KV cilia form prior to KV lumen formation using an intracellular pathway.

(A) Model depicting KV lumen formation across developmental stages of the zebrafish embryo. (B) Confocal micrographs of KV developmental stages with cilia (acetylated-tubulin, cyan), centrosome (γ-tubulin, magenta), and actin (phalloidin, gray). Scale bar, 10 μm. (b’) Magnified insets from (B) depicting centrosome and cilia positioning in KV cells at different KV developmental stages. Scale bar, 7 μm. (C) KV cell building and extending a cilium (Arl13b-mCardinal, gray) into the lumen of the KV. KV plasma membranes (Sox17:GFP-CAAX, cyan) shown. Scale bar, 5 μm. (D) Percentage of ciliated KV cells at the different KV developmental stages shown as a violin plot with median (yellow line). One way ANOVA across KV developmental stages, n>7 embryos, **p<0.01. (E) Scatter plot demonstrating the percentage of KV cells with lumenal cilia per embryo in relation to KV lumen area. n = 29 embryos. Goodness of fit R² = 0.8577. (F) Scatter plot depicting average cilia length within KV cells per embryo across n = 29 embryos in relation to lumen area. Error bars, ± SEM. (G) Violin plot depicting relative distance of cilia from cell border closest to KV center. median (yellow line). One way ANOVA across KV developmental stages, ***p<0.001. (D-G) Please refer to S1 Table for additional statistical information. (H) Model demonstrating intracellular versus extracellular pathways for cilia formation. (I) 3D surface rendering of representative KV cells with cilia (acetylated-tubulin, cyan) inside versus outside of KV plasma membranes (KV membranes, Sox17:GFP-CAAX, gray), Myo-Va (magenta). Scale bar, 5 μm.