The evidence presented here indicates that Alk contributes to behavioral responses to ethanol in invertebrates and mammals, including humans. Moreover, we found that dAlk expression is regulated by dLMO. LMO proteins are transcriptional regulators that function to repress or activate transcription through interactions with DNA binding proteins [26]. dLMO appears to repress dAlk expression, since dAlk increases in dLmo loss-of-function mutants. The ethanol sedation phenotype of dLmo and dAlk mutants is consistent with a negative regulatory role of dLMO on dAlk expression. The dLmo EP1306 mutant, in which dAlk expression is increased, showed increased sensitivity to ethanol sedation [20], whereas the dAlk f01491 mutant, with decreased dAlk expression, was resistant to ethanol sedation. These data define a novel regulatory pathway involved in ethanol-induced sedation in Drosophila melanogaster.
