Figure 8

Decrease of OE progenitors undergoing terminal division at E12.5 in Insm1^-/-mice. (A) Schematic of strategy for detecting terminally dividing cells within the embryonic OE. Pregnant dams were injected with 10 mM EdU at E12.5, followed by 10 mM BrdU 12 hours later at E13. Embryos were sacrificed at E14.5 and processed for immunohistochemical detection of BrdU and chemical detection of EdU. Cells produced by terminal division at E12.5 would be positive for EdU and negative for BrdU (green only; in the schematic as drawn, two cells out of the six). (B) Insm1^-/-mice had an average of 33% fewer terminally dividing progenitors than their paired Insm1^+/+and Insm1^+/-littermates (n = 3 embryo pairs, total of 9 aligned section pairs, P < 0.001). (C-F) Representative aligned coronal sections from (C, E) an Insm1^+/+embryo and (D, F) an Insm1^-/-littermate. EdU label is green and BrdU label is red. Open arrowheads indicate selected double-labeled cells and solid arrowheads indicate cells labeled only with EdU (11 in wild type (WT) compared to 6 in knockout (KO)). Solid white lines indicate the basal lamina (bottom), and dashed lines indicate the apical edge (nasal airway; top). Data in (B) are presented as mean values ± standard error of the mean (SEM). ***P ≤ 0.001. Scale bars: 50 μm.