An SEM AND TEM study of suppression of eye development in eyeless mutant axolotls.

Morphology of the primary optic rudiment of normal eyed and mutant eyeless (e/e) axolotl embryos was studied at light. Tem and SEM levels. The presumptive eyeforming region of eyeless embryos differs from that of normal embryos in several important respects including premature formation of basal lamina, separation from overlying ectoderm by mesenchyme cells and persistence of granules in the interspace surrounding the optic anlage into relatively late developmental stages. These differences suggest that the gene that causes failure of eye formation in the mutant axolotls produces structural differences that interfer with normal physical and/or biochemical inductive interactions between neurectoderm and mesenchyme cells due primarily to the precocious development of basal lamina over the extermal surface of the optic primordia.