Fig. 5. Retinal Pax6 expression is regulated in two complementary topographic domains. Staining for tau-ß-gal/ß-gal activity of P20 -tau-lacZ (A,C,D,G,I) and Pax6^lacZ/+ (B,E,F,H,J) eyes and brains. (A) Horizontal section of a -tau-lacZ eye reveals steep distal-to-proximal gradient of expression in the gcl, while Pax6^lacZ/+ eyes display a precisely complementary pattern of ß-gal activity (B). (C-F) Higher magnifications of the distal (C,E) and proximal (D,F) NR of -tau-lacZ and Pax6^lacZ/+ eyes shown in A and B, respectively. The -tau-lacZ NR displays strong expression in distal (C), but not in proximal (D) RGCs, while the Pax6^lacZ/+ shows strong expression in proximal (F), but no expression in distal (E) RGCs. (G-H) Dorsal view of the superior colliculus and ot of -tau-lacZ (G) and Pax6^lacZ/+ (H) brains. (G) In the -tau-lacZ brain, tau-ß-gal⁺ axons omit the central region of the superior colliculus (dotted circle), which is innervated by ß-gal⁺ axons in the Pax6^lacZ/+ brain (H, dotted circle), while the sickle-shaped domains stained in -tau-lacZ are devoid of ß-gal⁺ axons (compare G with H). (I,J) Sagittal sections through the of -tau-lacZ (I) and Pax6^lacZ/+ (J) mesencephalon reveals complementary innervation of the superior colliculus by tau-ß-gal⁺ and ß-gal⁺ axons. Arrowheads in I indicate single stained axons. -tlz, -tau-lacZ; cb, cerebellum; l, lens; onl, outer nuclear layer; pc, posterior commissure.

Return to article