Fig. 6

Internal MT network morphology. (A) Depth-coded projection of a z-stack in which the information relative to the outer YCL was digitally removed. The internal microtubule network and its extension within the yolk is visible. Visualized depths range between 0 µm (white) and 350 µm (blue). Vegetal view, left and right images of the embryo are stitched together, scale bar 200 µm. (B) Maximum intensity projection over a 40 µm range of a yolk section. The internal MTs forms circular patterns (white arrows) and also are connected to the external yolk MTs (eMTN) network. Vegetal view, left and right images of the embryo are stitched together, scale bar 200 µm. (C) Zoom (single slices) on the yolk surface, showing clear connections between the internal and external MT networks (white arrows, upper and lower panel), and interconnections between internal MTs (white arrow, lower panel). Scale bars 50 µm. (D) Embryo at sphere stage, lateral view. AP = animal pole, VP = vegetal pole, scale bar 200 µm. (E) zoom into the ROI indicated by * in (D), single slice, showing connection of internal MTs to an eYSN (white arrows). eMTN = external MT network, scale bar 50 µm. (F) Maximum intensity projection over a 20 µm range of the same ROI showing also the extension toward the internal portion of the yolk of the MT connected to an eYSN. Scale bar 50 µm. See also Visualization 5. (G) zoom into the ROI indicated by ** in (D), single slice, showing an internal MT bundle (white arrow) extending perpendicular to the image plane. (H) Maximum intensity projection showing the end point of that internal MT bundle, coinciding with a centriole (white arrow) associated to an eYSN. (I) An XZ re-slice view of the same ROI showing the connection of the same MT bundle and its extension toward the interior of the yolk. Scale bars 50 µm. See also Visualization 4. All figures relative to dclk2-GFP embryos, and Orange HOT lookup table was used to ease iMTN visualization.