The Earth rotation causes periodic changes of light and temperature. A prediction of daily environmental changes has survival advantages to an organism which can adapt its behavior and physiology to the appropriate time of the day. For the reason, natural selection has favored the evolution of circadian clocks. The circadian clock consists of three parts, the input pathway, central clock oscillator, and output pathway. The Six groups of Drosophila clock pacemaker cells are revealed in adult fly brain. They are small and large lateral ventral neurons, lateral dorsal neurons, and three groups of dorsal neurons. The molecular components of the circadian pacemaker cells form two interlocked transcriptional negative feedback loops. In one loop, dCLK/CYC activates per and tim gene expression, and PER/TIM then inhibits dCLK/CYC activity. In the other loop, dCLK/CYC also activates vri and Pdp1ε gene expression, and VRI and PDP1ε then repress or activate dClk transcription.
In this study, we focused on the study of Pdp1ε gene. We developed a screen method to find out the genetic modifiers of Pdp1ε. Eye phenotype changes by overexpressed PDP1ε were used as the assay system for its genetic modifiers. The effect on the circadian behavior of candidate modifiers was also investigated. Moreover, two transgenic flies were also generated. One is Pdp1 -GAL4 driver and the other is Pdp1 RNAi strain. Features of them on the circadian system were also tested.