Using en-face optical coherence tomography to analyse gene function in Drosophila Melanogaster larval heart

In-vivo Optical Coherence Tomography (OCT) imaging of the fruit fly Drosophila Melanogaster larval heart allows non invasive visualizations and assessment of its cardiac function . In order to image Drosophila heart, we have developed a dedicated imaging instrument able to provide simultaneous OCT and Laser Scanning Confocal Microscopy (LSCM) images. With this dual imaging system, the heart can easily be located and visua lised within the specimen and the change of the heart shape in a cardiac cycle monitored. Here we have used targeted gene expression to knockdown the myospheroid (mys ) gene in the larval heart using a specific RNAi construct. By knocking down a E integrin subunit encoded by mys we have recorded an enlarged heart chamber in both diastolic and systolic states. Also, the fraction of reduction of the chamber diameter was smaller in the knockdown heart. These phenotypic differences indicate that impaired cardiac contractility occurs in the heart where the integrin gene express le vel is reduced. At our knowledge, this is for the first time when it is shown that integrins have a direct relationship to a dilated heart defect. Keywords: Optical Coherence Tomography, Laser Scanning Microscopy, Drosophila Melanogaster, larva, developmental biology, heart, cardiomyopathy