TEMPERATURE REGULATES EXPRESSION OF THE DROSOPHILA VESTIGIAL GENE ONLY IN MUTANT WING DISCS

All Vestigial mutants in Drosophila melanogaster display a thermosensi tive phenotype, with the exception of two which disrupt an intronic wi ng-specific enhancer element. Here we report a very unusual transcript ional regulation; temperature changes are associated with alterations in the level of vg expression only in the wing disc of thermosensitive mutant flies and not in the brain. No effect is observed in the wild- type strain. The tissue specificity of the temperature effect indicate s an involvement of the intronic wing-specific enhancer element in det ermining the thermosensitivity of mutants.