Figure 3: Wdr5 is necessary for uniform distribution and polarization of basal bodies.

(A) The four steps of ciliogenesis in MCCs: 1) MCCs are specified in the deeper epithelial layer, 2) MCCs insert themselves into the superficial epithelia. They simultaneously begin basal body biogenesis deep in the cytoplasm, 3) Apical enrichment of actin leads to apical expansion of MCCs. Basal bodies also start to migrate and dock to the apical surface, and 4) Basal bodies dock, distribute evenly, and orient at the apical surface, which leads to ciliogenesis. Cilia mediated flow then reinforces basal body polarity.

(B-D) Wdr5 is essential for uniform basal body distribution in MCCs. (B) MCC showing uniform and clumped distribution of basal bodies (Centrin-RFP) in uninjected control and wdr5 morphant respectively. Control MCC is divided into 4 quadrants labeled Q1–4 with different colors to use for quantification of distribution pattern in (D). n = number of MCCs.

(C) Basal bodies from 6 individual MCCs from different embryos are overlaid on each other to show loss of uniform distribution of basal bodies in wdr5 morphants. Basal bodies from each MCC are colored differently.

(D) Quantitative analysis of basal body distribution in uninjected controls and wdr5 MO injected embryos. Each MCC was divided into 4 quadrants and the number of basal bodies in each quadrant are plotted on their respective axes (Q1-Q4, see panel D). We measured number of basal bodies in each quadrants for 6 MCCs. In the graph, each color represents one MCC. Squareness represents uniform distribution of basal bodies in a MCC.

(E-G) Wdr5 is essential for planar organization of basal bodies in MCCs. (E) MCCs showing parallel and random orientation of rootlets (Clamp-GFP, magenta) with relation to basal bodies (Centrin-RFP – cyan) in controls and wdr5 MO injected embryos respectively.

(F) Quantitative analysis of basal body polarity with angular velocity graphs. Each color represents a MCC (10 total) and axes show orientation of rootlets for 20 basal bodies per MCC. Length of axis represents angle of orientation (0–360). Circularity depicts rootlets are parallel to each other and basal bodies are planar polarized.

(G) Angular velocity graph showing standard deviation in the orientation of rootlets. Here, each axis represents each MCC and length represents standard deviation in angle of orientation of 20 rootlets within each MCC. Standard deviation is smaller in controls, as rootlets are more parallel to each other compared to wdr5 MO injected embryos. ★★ indicate statistical significance at P < 0.005.