FUNCTIONAL DOMAIN ANALYSIS OF GLASS, A ZINC-FINGER-CONTAINING TRANSCRIPTION FACTOR IN DROSOPHILA

The glass gene is required for proper photoreceptor differentiation du ring development of the Drosophila eye. glass codes for a DNA-binding protein containing five zinc fingers that we show is a transcriptional activator. A comparison of the sequences of the glass genes from two species of Drosophila and a detailed functional domain analysis of the Drosophila melanogaster glass gene reveal that both the DNA-binding d omain and the transcriptional-activation domain are highly conserved b etween the two species. Analysis of the DNA-binding domain of glass in dicates that the three carboxyl-terminal zinc fingers alone are necess ary and sufficient for DNA binding. We also show that a deletion mutan t of glass containing only the DNA-binding domain can behave in a domi nant-negative manner both in vivo and in a cell culture assay that mea sures transcriptional activation.