ECTOPIC LENS INDUCTION IN FISH IN RESPONSE TO THE MURINE HOMEOBOX GENE SIX3

Recent findings show an unexpected conservation of genes involved in v ertebrate and insect eye development. The Drosophila homeobox gene sin e oculis is crucial for eye development. Its murine homologue, Six3 is expressed in the anterior neural plate, a region which is involved in lens induction in Xenopus. To examine whether Six3 participates in th e process of eye formation, mouse Six3 was ectopically expressed in fi sh embryos. The results show that Six3 is sufficient to promote ectopi c lens formation in the area of the otic vesicle and that retinal tiss ue is not a prerequisite for ectopic lens differentiation. Our finding s suggest a conserved function for Six3 in metazoan eye development.