Investigating the Expression of the Gene Dronc in Drosophila melanogaster

Abstract

Programmed Cell Death (PCD) is the process whereby cells undergo self-destruction for development or maintenance of homeostasis. Apoptosis, a form of PCD, is highly regulated by a series of molecular signals. In Drosophila melanogaster the steroid hormone 20-hydroxyecdysone (ecdysone) controls tissue development and metamorphosis (Bond et al., 2010; Yamanaka et al., 2013). My goal was to explore the role of ecdysone in PCD. A pulse of ecdysone occurs at 10 hours after puparium formation (APF), inducing the prepupal-pupal transition (Lee et al., 2002). In response to this ecdysone pulse, salivary gland cells undergo apoptosis (Lee et al., 2002). At the same time, ecdysone induces dissociation of fat body cells (Bond et al., 2011). It is my goal to add to the dataset of Cavale (2023), by comparing Dronc in the same tissues: salivary glands (experimental) and the fat body (control). Due to the spatiotemporal spread of ecdysone, anterior and posterior sections of the fat body were analyzed separately. Gene expression was quantified by RT-qPCR, and when possible, a standard curve was included to account for individual primer efficiencies. Two-way ANOVA analysis showed no significant difference between the Dronc expression at 10 and 12 hrs. APF (p=0.142), nor in the Dronc expression between anterior and posterior fat body cells (p=0.186). There was also no significant evidence that the positioning of the fat body (anterior or posterior) influenced Dronc expression (p=0.571) at the two timepoints. To further investigate the anterior/posterior differences, the Dronc expression of each anterior sample was divided by its posterior counterpart. Assuming no difference, the ratio should be 1. A one-sided t-test showed significant difference between the observed and theoretical anterior/posterior ratio of 1 at 10 hrs. APF (p=0.043), but the difference was insignificant at 12 hrs. APF (p=0.197).