CLASP and LL5s are involved in regulating basal MT dynamics. (A) Diagram of eGFP-EB1 electroporation and live-embryo imaging. (B) Imaging of lateral epiblast cells from the apical side. eGFP-EB1 molecules show dynamic and radial movement from the center toward the rim of the cell. (C) Imaging of lateral epiblast cells from the basal side. EB1 signals in the apical, middle, and basal planes in control MO cell (top) or CLASP1 and LL5s MO cell (bottom). In the latter cell, EB1 signals are relatively weaker basally. Right-most panels are examples of 3D-reconstituted images showing the difference in eGFP-EB1 signals between control and CLASP/LL5s knockdown cells. (D–F) Quantification of relative basal eGFP-EB1 signal intensity in frozen sections. (D) Examples of cellular morphology with electroporated control MOs (left) and triple MOs (middle, mild phenotype; right, severe phenotype). Only triple MO cells with mild phenotype are used in quantification. Broken lines outline individual epiblast cells. (E) Relative eGFP-EB1 intensity is calculated as a ratio between basal cortical signals and total cellular signals. (F) Mean relative basal eGFP-EB1 signal intensity in cells (n = 50) without MO, with standard MO, or with triple knockdown MOs. (G) Relative intensities are shown as proportions of cells with their basal eGFP-EB1 signals representing the 10th, 20th, 30th, and 40th percentiles of total eGFP-EB1 signals. Error bars indicate one standard deviation. Bars, 5 µm.