Fig 4. Genoarchitectonic signature of the Di-Mesencephalic primordium (DiMes).

(A-A′′) Combined Fezf-Gbx expression defines a gap of expression in the caudal archencephalic prototagma (ARCH), identified as the DiMes (as per Fig 3K and 3L, for reference). (B-E′′) Whole-mount chromogenic in situ hybridization of Pax4/6 (B-B′′) or Six3/6 (D-D′′) alone or each one combined with Gbx in a double in situ hybridization (C-C′′ and E′-E′′, respectively) reveal that both genes are expressed in the DiMes domain. The two arrowheads in (D) indicate the expression of Six3/6 in Rostral-hypothalamo–prethalamic primordium (Rostral-HyPTh). (F-F′′) Pou3f is highly expressed in DiMes but with a decreased signal in the Rostral-HyPTh and Intermediate-HyPTh primordia and in some areas of the deuteroencephalic prototagma (DEU). (G-G′′) Ebf mRNA was detected in the DiMes and DEU domains. (H-H′′) Sim neural expression was observed exclusively in the DiMes domain at the analyzed stage. Expression patterns correspond to lateral (A-H) or dorsal views (A′-H′) at the 21 h post fertilization (hpf) embryonic stage and are represented in schematics dorsal views (A′′-H′′). Somites (dotted lines) were used as main landmarks to localize the position of the patterns analyzed in the late neural plate. Scale bar: 50 μm.