Recently we found that the Drosophila LIM-domain only (dLMO) transcriptional regulator controls sensitivity to ethanol-induced sedation [20]. To identify novel transcriptional targets of dLMO that might mediate its effects on behavioral responses to ethanol, we performed gene expression microarray analysis of flies carrying either a dLmo loss-of-function mutant, EP1306 [18], or a gain-of-function mutant, BxJ [23], [24]. We discovered 555 genes, out of 18,952 surveyed, whose expression was significantly altered in one or both of the dLmo mutants compared to control flies (Table S1). The 555 genes were clustered using the HOPACH algorithm [25], resulting in 7 clusters. Since the classically described function of dLmo is negative transcriptional regulation of genes [26], we focused on cluster 3, containing 43 transcripts exhibiting increased expression in the dLmo loss-of-function and decreased expression in the dLmo gain-of-function mutant. The gene encoding the fly homolog of anaplastic lymphoma kinase (dAlk), encoding a receptor tyrosine kinase in the insulin receptor superfamily, was a member of this cluster (Figure 1A). dAlk expression was decreased by 14% in BxJ flies and increased by 26% in EP1306 flies.
