Figure 3.

Biological consequences of Otx2 invalidation at embryonic day (E)10.5, E12.5, E14.5 or E16.5. (A) Genotype distribution, at E18.5 and P10, of F1 animals (Fig 1A) that received tamoxifen (Tam) at the indicated time or solvent (Mock). The number of individuals analysed is indicated at the top of the bars. (B) Morphology of E14.5 and P0 Otx2^flox/CreERT2 mice after tamoxifen injection at E10.5. Scale bars, 2 mm. (C) Size comparison of 10-week littermates of the indicated genotypes that received tamoxifen at E12.5. (D) Weight distribution of animals of the indicated genotypes at P10, 3 weeks and 10 weeks after birth versus time of tamoxifen (Tam) or solvent (Mock) injection. Histograms represent mean value and error bars are standard deviation. The number of animals in each series is shown at the bottom. ^*P<0.001 after Student's t-test. (E–L) Anatomical and histological comparison of midbrain/hindbrain development at P10. Dorsal view of the brain (E–H) and Nissl-stained sagittal sections (I–L) of animals that received tamoxifen at E12.5 (E,I), E14.5 (F,J), E16.5 (G,K) or solvent (H,L). Arrows point to the inferior colliculi. The arrowhead points to the granular-like staining of the mesencephalon. Asterisk shows size and foliation defects of posterior cerebellum. ic, inferior colliculus; sc, superior colliculus. (M–P) Alkaline phosphatase activity in sagittal sections of brains of P10 Otx2^+/CreERT2 ; Z/AP animals that received tamoxifen at time corresponding to the panels above. Scale bars, 2 mm. (Q–T) Histological organization of ectopic cerebellar-like structure (Ecto) and endogenous cerebellum (Endo) of an adult Otx2^flox/CreERT2 animal that received a single injection of tamoxifen (Tam) at E12.5. Haematoxylin–eosin staining (Q), calbindin immunofluorescence (white arrowheads) (R), GAD67 in situ hybridization (S) and calretinin immunofluorescence (T) on sagittal sections. Scale bar, 500 μm.