Acquisition of an Olympus SZX7 fluorescent stereo microscope for dissecting late-stage Drosophila embryos and selecting Drosophila embryos with GFP/RFP tagged genes

Oakland University, Rochester MI

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Abstract

Acquisition of an Olympus SZX7 fluorescent stereo microscope for dissecting late-stage Drosophila embryos and selecting Drosophila embryos with GFP/RFP tagged genes This proposal is for the acquisition of an Olympus SZX7 fluorescent stereo microscope to replace an old and broken fluorescence stereo microscope, which was used to select GFP- positive fly embryos and dissect fly embryos when ring light is provided. The awarded NIH R15 research project is to study the role of a poorly understood Osiris (Osi) gene family in regulating tube maturation in Drosophila trachea, which is a premier system to reveal fundamental mechanisms of tubular organ formation. The Drosophila trachea is a ramifying network of epithelial tubes with a monolayer of epithelial cells surrounding an apical lumen. During tube maturation, the apical secretion burst deposits large amounts of luminal matrix components to the apical lumen. Then, this lumen is cleared before air fills the lumen. The goal of the awarded project is to reveal the functions of Osi proteins as “broader coordinators” of protein trafficking during tube maturation. To test this hypothesis, we will complete the following three specific aims: Aim. 1 Determine the function of Osi genes in the trafficking of the apical luminal matrix during tube maturation. Aim. 2: Determine the function of Osi genes as coordinators to control endosome-mediated protein trafficking. Aim. 3: Identify proteins that directly bind to Osi proteins. To carry out the proposed experiments, we will analyze protein trafficking and structural changes in late-stage embryos by immunostaining. In addition, we will analyze the dynamic coordination of vesicular trafficking in vivo by observing GFP-tagged vesicle markers and RFP-tagged protein markers simultaneously in Osi mutant background. The tracheal phenotypes in Osi mutants appear in late-stage embryos (mid-stage 17). Due to cuticle formation, antibodies cannot enter embryos effectively without dissection. Therefore, we need to dissect the late-stage embryos before immunostaining. In addition, we will generate fly strains that carry GFP-tagged vesicle markers and RFP-tagged luminal protein markers in Osi mutant background. Since some marker genes are located on the same chromosome as Osi genes, we will recombine these marker genes to Osi mutant background genetically. Therefore the potential live recombinant fly embryos that carry GFP- or RFP- tagged marker genes can be selected using a stereo fluorescent microscope. Unfortunately, our old fluorescence stereo microscope that can be used to dissect late-stage fly embryos as well as to select live embryos that carry fluorescently tagged genes is broken beyond repair. Thus, this requested Olympus SZX7 fluorescent stereo microscope will allow us to carry out the proposed experiments (Aim. 1 and Aim. 2) on time. Without it, our progress on the project will be significantly delayed.