Fgf8-Related Secondary Organizers Exert Different Polarizing Planar Instructions along the Mouse Anterior Neural Tube
Figure 1
Phosphorylation patterns of ERK1/2 (dpERK) enzymes in the anterior neural tube.
Whole mount in situ hybridization (ISH) of E9.5 mouse embryo (A,B,B’) and corresponding organotypic neural tissue cultures of mouse E9.5 anterior neural tube (A’,B”,C-E”; ONTCs; [42]) where it shows the maintenance of gene expression profiles such us Fgf8, Tcf4 (A,A’) (used to delimit main brain subdivisions such the diencephalon (D; Tcf4 positive) and the mesencephalic anlage (M; negative staining), Pax6 D-D” (delimiting di-mesencephalic boundary and rhombomere 1–2 limits) and En2 E-E”. In B-B”) are photomicrographs of E9.5 mouse embryo with anti-dpERK Immunohistochemistry (IHC) taken from lateral (B) and caudal (B’) sides and the corresponding IHC in ONTCs. (C) double staining procedure: ISH (in blue) for Fgf8 and IHC for dpERK (dark brown) to localize inside the dpERK domain the position of the IsO, marked by the solid red line. (D-E”) photomicrographs of same ONTCs in which first a whole mount ISH for Pax6 (D) or Tcf4/En2 (E) were made and afterwards IHC against dpERK. (D’,E’ respectively). Dashed lines mark the main transversal (in black) and longitudinal (in red) brain subdivisions. These ONTCs were cut into transversal sections to the isthmic constriction (D”,E”) to proof that indeed dpERK expression reaches diencephalic anlage (D”; see asterisk; rostral is left) and has a wider expansion than En2 expression (E”; see asterisk; rostral is left). anr is anterior neural ridge secondary organizer; ba is branchial arch; IsO is isthmic organizer; os is optic stalk; ov is otic vesicle; r is rhombomere; T is telencephalon, D, diencephalon, M, mesencephalon. Scale bars are 0,5 mm except in D”, E” they are 100 µm.