Figure 3
Acidification of intracellular compartments of E5.5 embryos required the c-subunit of V-ATPase. The signal of the c-subunit (red) (wild-type: n = 9, mutant: n = 12) accumulated at the apical region of VE cells in E5.5 embryos (a to d). Lamp2 (green) and GATA6 (blue) signals are also shown. The boxed areas of b1 and d1 are enlarged images showing the signals of c-subunit in VE cells, and the boxed region of b2 and d2 are those of PE cells (shown by the arrow). The c-subunit (red) signal overlapped with the early endosome marker, sorting nexin1 (SNX1) in E5.5 wild-type embryos (n = 3) (e to g). The localisation of SNX1 in mutant embryos appeared dispersed (n = 4) (h to j). VE, visceral endoderm; PE, parietal endoderm. The E6.0 wild-type embryos were labelled with LysoTracker (LT) in the presence (k and n) (n = 4) or absence of bafilomycin A1 (Baf A1) (n = 14) (l, m, o, and p). The sagittal images (LT in red, Lamp2 in green, and Topro3 in blue) and para-sagittal images (LT in red, Lamp2 in green, and SNX1 in blue) are shown. The signal of LysoTracker was surrounded by the signal of SNX1 (m and p). LysoTracker staining of E5.5 wild-type (n = 17) (q and r) and Atp6v0c mutant embryos (n = 3) (s and t). The boxed regions in r and t are enlarged, and scale bars in panels a, c, b2, d2, k–m, and q–t, are 20 µm, scale bars in panels b1, d1, e–j, n–p, and 1–4 are 5 µm.
