Exploring the Role of the Arp2/3 Complex and the Formin, Diaphanous, in the Germline Ring Canals of the Developing Drosophila Egg Chamber

Josephine Thestrup Butler University, Marina Tipold Butler University, Alex Kindred Butler University
Faculty Sponsor(s): Lindsay Lewellyn Butler University, Kayla Harpold Butler University
Proper gamete formation is necessary for fertility in sexually reproducing organisms, and intercellular bridges are an essential structure found in the developing sperm and eggs from insects to mammals. The largest and best studied intercellular bridges are found in the developing fruit fly egg chamber. These intercellular bridges, or ring canals, connect the developing oocyte to supporting nurse cells; they allow these neighboring cells to exchange material such as RNA, protein, and organelles, and defects in ring canal stability or expansion lead to infertility. The ring canals are enriched in actin and actin binding proteins, and ring canal expansion depends on the activity of the Arp2/3 complex, which nucleates the formation of branched actin filaments. Mutations in members of the Arp2/3 complex lead to smaller and collapsed ring canals. However, it is not known when during oogenesis these defects arise, or whether another actin nucleator, the formin, Diaphanous, is also required for ring canal formation or expansion. In this study, we use the GAL4/UAS system to study the effect of depletion of either the Arp2/3 complex member, ArpC2, or the formin, Diaphanous (Dia), from the developing germline. After verifying the specificity of the UAS-RNAi lines using qRT-PCR, we measured mature egg size, ring canal diameter, and the levels of various ring canal proteins in control, arpC2-RNAi, and dia-RNAi egg chambers. Our preliminary results suggest that the Arp2/3 complex is necessary to regulate ring canal size throughout oogenesis, whereas Dia is primarily important during the early stages of oogenesis.
Oral Presentation

When & Where

09:00 AM
Gallahue Hall 105