Mechanism of the fluorescent light induced suppression of curly phenotype in Drosophila melanogaster

A dominant mutation Curly (Cy), frequently used as a marker on the second c hromosome in Drosophila melanogaster, was previously shown to be suppressed by several factors, including larval crowding, low temperature, and fluore scent light. While the first two factors affect this mutation only partiall y, fluorescent tube exposed flies exhibit an almost completely suppressed ( wild type) phenotype. This suppressive effect is the result of a combinatio n of the electric field and light, both factors being produced by common fl uorescent tubes. In this study, experiments were carried out to clarify the basic mechanism of this unique phenomenon. Two fluorescent tube sensitive stages of Drosophila development were found in the second half of embryonic development and first half of the pupal stage. Riboflavin, which is admini stered to Drosophila larvae with yeast, and decomposed by light, seems to p lay a key role in this phenomenon. In a medium lacking riboflavin caused by light exposure, Cy expression is inhibited by the action of electric field . Positive results of experiments with lithium ions, which block the openin g of Ca2+ channels, support the hypothesis that electromagnetic fields may alter ion currents during ontogenic development of Drosophila, and thus inf luence, expression of the Cy gene. Also, fluorescent light induces an overe xpression of a specific protein in the imaginal wing disc of Cy pupae. Bioe lectromagnetics 22:371-383, 2001. (C) 2001 Wiley-Liss, Inc.