I am m working on the regulatory network that determines larval photoreceptors and the developmental switch in rhodopsin expression during metamorphosis.
The eyes of Drosophila larvae consist of 12 photoreceptors: Four primary receptors expressing rhodopsin 5 (Rh5) and eight secondary receptors expressing rhodopsin 6 (Rh6). During metamorphosis the eight Rh6 expressing cells undergo apoptosis, while the remaining four photoreceptors develop into the adult eyelet by switching off Rh5 expression, activation of Rh6 expression, and production of histamine as neurotransmitter in addition to acetylcholine used during larval stages. These changes are induced by ecdysone signaling triggering metamorphosis. While the function of some transcription factors regulating rhodopsin expression in larval photoreceptors has been demonstrated, the exact interplay of signaling molecules and transcription factors to regulate specific gene expression in the larval eye and upon transition to the eyelet has not been resolved. I intend to determine the regulation and interplay of genes involved in larval photoreceptor development by looking at the expression dynamics of transcription factors and how they regulate their target genes.