Fig. 1 Maternal expression disappearing progressively during late blastula from animal pole to marginal region. No staining in YSL. Expression maintained stronger in dorsal region

Fig. 2 At the onset of gastrulation the expression of Sef is restricted to the margin. This marginal expression is maintained all along the gastrulation. Expression of Sef is observed in axial hypoblast from the shield stage to the end of gastrulation. Anteriorly Sef is present in posterior prechordal plate but excluded from anterior prechordal plate (presumptive hatching gland territory). After 80% epiboly another expression territory appears in anterior neural plate (presumptive forebrain).

Fig. 3 At the bud stage the marginal expression at gastrulation encompass about 1/4th of the embryo in posterior region including the tail bud. Staining is observed in axial mesoderm, forebrain and anterior paraxial mesoderm
By the 1 somites stage the expression of Sef is observed in telencephalon, eye field. At the 2 somites stage Sef start to be expressed at the midbrain hindbrain boundary. At the 5 somites stage, expression is strong in telencephalon,at the midbrain-hindbrain boundary, notochord, presumptive branchial arches mesoderm, somites (but not in adaxial cells). Posteriorly, a staining is observed in ventral spinal cord and lateral neural plate. A very strong expression is observed in unsegmented paraxial mesoderm and in tail bud

Fig. 4 At middle somitogenesis, staining increases in telencephalon, optic stalk, midbrain hindbrain boundary, but disappears from hindbrain. Otic placode express Sef. A strong expression is also observed in presumptive branchial arches, somites, and tail bud. No staining i s observed in notochord and adaxial cells but posteriorly an expression is detected in hypochord.

Fig. 5 Expression is very strong at the midbrain hindbrain boundary, in optic stalk and branchial arches. Expression appears in lens, olfactory vesicle, lateral line primordium, pectoral fin bud and dorsal diencephalon. Expression is maintained in telencephalon, tail bud and otic vesicle. In anterior somites, adaxial cell start to express Sef Caudally the remaining expression in somites is observed in the most anterior cells of each somites.Sef expression in most territory follow expression of FGF8. In branchial arches Sef expression follows the expression of FGF3.

Fig. 6 Expression of Sef at 36 h is similar to its expression at 24 h. Adaxial staining increases and the line of cells that give rise to slow muscles fibers is now completely labeled. In tail the axial fin fold starts to express Sef.

Fig. 7 In addition to the previous site of expression Sef is observed in dorsal posterior hindbrain as well as in a diencephalic nuclei dorsal to the optic chiasm (supra chiasmatic nucleus?).