Assessing a Possible Regulatory Network of Obp56h in Drosophila Melanogaster

Mating behavior is a complex phenotype that can be controlled by changes in gene expression. Odorant binding proteins, such as Obp56h, are involved in male mating performance in Drosophila melanogaster. Obp56h allows an inhibitory sex pheromone to be sensed by males, making them less inclined to mate. As Obp56h expression decreases, courtship latency also decreases. However, the regulatory pathway that controls the gene's expression is not well understood. Here we show that CG2120, a gene that is negatively co-expressed with Obp56h, may be regulating Obp56h expression. We find that in CRISPR/Cas9 overexpression of CG2120 in males with Apolpp and Elav drivers for Gal4 resulted in decreased courtship latency when mated with Canton S virgin females but not significantly with Oregon R. We also find that the Apolpp-Gal4 lines had a higher percentage of successfully mated males than the Elav-Gal4 lines. Our results align with the hypothesis that CG2120 may be negatively regulating Obp56h and therefore, decreasing courtship latency. We anticipate that further data collection to the behavioral assay will substantiate our findings. Changes in Obp56h expression have not been studied, and fertility is currently being studied. Further workup using qRT-PCR will enable us to quantify whether Obp56h expression decreases in upregulated CG2120 groups. Obp56h expression is a fitness-related phenotype making it relevant to understanding the evolution of mating behavior.