Abstract
During mid-oogenesis of Drosophila, cytoplasmic particles are transported within the nurse cells and through ring canals (cytoplasmic bridges) into the oocyte by means of a microfilament-dependent mechanism. Video-intensified fluorescence timelapse microscopy, in combination with microinjections of antibodies directed against Drosophila 95F myosin, have revealed that this unconventional myosin of class VI is involved in the transport processes. The results indicate that certain cytoplasmic particles in the nurse cells move along microfilaments due to their direct association with myosin VI motors. Additional myosin-VI molecules located at the rim of the ring canals seem to be involved in particle transport into the oocyte. Microinjected mitochondria-specific dyes have revealed that some of these particles are mitochondria.