Investigation of the role of IroC in asymmetric cell division

Abstract

Drosophila melanogaster olfactory system has a high range of neural diversity. During pupal development, Olfactory Receptor Neurons (ORNs) are diversified within the sensory organ lineage emerges from a Sensory Organ Precursor (SOP). ORN diversification is the initial phase increases the neural diversity in olfactory system. Various cell fate determinants act on precursor cells of ORNs in a combinational code and enable ORNs to acquire different cell fates. Cell fate determinants are distributed throughout the sensory organ lineage by asymmetric cell division and they can be used as cell type specific markers. By using these markers, we aimed to elucidate the function of our gene family of interest, IroC (Iroquois complex) in asymmetric cell division during olfactory system development. The Iroquois Complex (IroC) consists of three different genes in Drosophila: araucan (ara), caupolican (caup), and mirror (mirr) that are located on the third chromosome. IroC is shown to be expressed in antenna and maxillary palp, two olfactory organs of Drosophila. I aimed to understand the expression profile of IroC and confirm the previously determined expression pattern using Gal4 lines. To achieve this aim, I conducted experiments by using different constructs to get a better idea about the expression pattern of iro proteins. To study function of iro proteins, I conducted clonal analysis experiments with using different cell-type specific markers in IroC triple mutant and caup single mutant backgrounds. Analysis showed that in the absence of iro proteins, Notch protein cannot be functioned and Notch downstream genes are negatively affected. Thus, iro proteins act as cell fate determinants.