CHARACTERIZATION OF DROSOPHILA MELANOGASTER FONDUE MUTANTS
Efficient clotting is essential to invertebrates with open circulatory systems. Like blood clotting in vertebrates, coagulation is important to stop bleeding and prevent bacteria from entering at the wound site of invertebrates. Multiple Drosophila clotting factors have been identified and work has started to study the effects of a few in vitro and more importantly in vivo. Here we characterize the fondue clotting factor mutants. Effects are seen in vitro for fon RNAi knock downs, hypmorph mutants, and null mutants we generated by excising a Minos element. However, with the current in vivo assay, no coagulation phenotype is observed. We developed a new quick and easy in vivo assay, called the capillary assay, to measure how much wounded larvae bleed. Although findings from this assay showed strong results for hmlf03374 mutants, fon mutants still showed no in vivo phenotype with this assay. This reinforces the idea of redundant hemostatic mechanisms in Drosophila larvae. In addition to coagulation phenotypes, fon mutants are pupal lethal and have an elongated pupal shape. Driving the expression of fondue-GFP fusion construct showed that fondue is expressed in a stripped pattern along the body of the larvae. The similarity of this pattern to the expression pattern of tiggrin, a protein involved in muscle attachment, led to the discovery that some clotting factors, including fondue, act in muscle attachment in Drosophila.