Fig. 9. Developmental changes in lacZ expression with the F12placZ construct. Lateral (A,B,E,F) and frontal (C,G) views of transgenic embryos following ß-galactosidase staining. Transverse and sagittal sections of the transgenic embryos at 11.5 (D) and 12.5 (H-K) dpc. (A) lacZ expression is detected initially in the cranial portion of the first branchial groove and nasal regions (arrowhead) at 9.5 dpc. bg, branchial groove; d, diencephalon; e, eye; m, mesencephalon; ma, mandibular arch; ha, hyoid arch; ie, inner ear; na, nasal pits; oe, olfactory epithelium; pi, pinna; pl, pigment layer of retina; t, telencephalon.