Figure 6

Mitotically active (pH3+) progenitors decrease basally and increase apically in the OE of Insm1^-/-embryos. (A,D,G) Representative images from coronal sections of Insm1^+/+mice. (B,E,H) Anatomically aligned section pairs from paired Insm1^-/-littermates. Dorsal is toward the right, ventral toward the left. (A-C) At E10.5, there is no statistically significant difference in pH3+ cells overall, or at either the apical or basal border of the OE (n = 4 embryo pairs, total of 12 aligned section pairs, P = 0.36 overall, P = 0.25 apically, P = 0.57 basally). (D-F) At E12.5, Insm1^-/-mice exhibit no difference in overall numbers of pH3+ (green) cells when compared with Insm1^+/+littermates, but an average 42% increase in pH3+ cells in the apical subpopulation (P < 0.05), and an average 45% decrease in the basal subpopulation (P < 0.01; n = 4 embryo pairs, total of 13 aligned section pairs). (G-I) By E14.5, there is still no difference in overall pH3+ cells between Insm1^-/-mice and their paired Insm1^+/+or Insm1^+/-littermates, and there is also no significant difference between pH3+ cells in the apical subpopulation. However, there remains a 35% decrease of mitotically active cells in the basal subpopulation (P < 0.05; n = 4 embryo pairs, total of 22 aligned section pairs). Solid white lines delineate the basal lamina and dashed lines delineate the apical edge (nasal airway). Data in (C, F, I) are presented as mean values ± standard error of the mean (SEM). *P ≤ 0.05, **P ≤ 0.01. Scale bars: 100 μm.