Fig. 7

The cytoplasmic protrusion of secretory ameloblast and small intestine epithelial cells are deformed in the Satb1^−/− mice. A Circumferential F-actin belt-like structure (in red) was detected along the apical end of wt SAB, and branched F-actin bundle was detected in the Tomes’ processes (TP). B No apparent F-actin assembly was detected at the apical end of the Satb1^−/− SAB. C EPS8 was immunolocalized in the Tomes’ processes (indicated by black triangles) of wt SAB. D There was no Tomes’ process and concentrated EPS8 signal that could be detected in the Satb1^−/− SAB. E qPCR analyses on ameloblasts collected from mouse first molars showed that EPS8 was significantly upregulated up to 5.6-fold in wt SAB vs wt PAB. However, EPS8 expression levels in the Satb1^−/− PAB and SAB were similar to that detected in wt PAB. F The well-developed microvilli (indicated by black triangles) were detected along the lining of wt mouse small intestine. G Microvillus layer on the surface of the Satb1^−/− mouse small intestine was thinner and less consistent (indicated by black triangles). H, H′ Immunofluorescent staining with EPS8 antibody demonstrated that EPS8 was concentrated and aligned toward wild-type mouse small intestine brush border (in green). Phalloidin-labeled F-actin was well distributed along the brush border (in red). I, I′ EPS8 immunoreactive signal (in green) and F-actin architecture (in red) were less intense and organized at the apical surface of Satb1^−/− mouse intestinal epithelial cells. Scale bars in F, G, H′, and I′, 10 μM