Pax-6 genes, known to be essential for eye development, encode an evolutionarily 
conserved transcription factor with two DNA-binding domains. To corroborate the 
contribution of each DNA-binding domain to eye formation, we generated truncated 
forms of the Drosophila Pax-6 gene eyeless and tested their capacity to rescue 
the ey(2) mutant. Surprisingly, EY deleted of the homeodomain rescued the ey(2) 
mutant and triggered ectopic eyes morphogenesis. In contrast, EY lacking the 
paired domain failed to rescue the ey(2) mutant, led to truncation of 
appendages, and repressed Distal-less when misexpressed. This result suggests 
distinct functions mediated differentially by the two DNA-binding domains of 
eyeless.