The consequence is that nurse cell nuclear position is not maintained and the nuclei can block the flow of cytoplasm through ring canals. The product of the chickadee gene, profilin, is probably involved with initial events leading to rapid actin filament polymerization. The quail and singed genes each encode proteins that can bundle actin filaments. Although the functions of fascin and villin are biochemically and genetically distinct, we are have found that over-expression of quail protein can compensate for loss of fascin. The left panel is a drawing of a Drosophila egg chamber showing the position of the oocyte and the nurse cells.
Cytoplasm flows into the oocyte through ring canals connecting the nurse cells to the oocyte.
The right panel is an egg chamber stained with an antibody to the ring canal-specific hts protein showing the normal complement of 15 ring canals. The villin-like protein encoded by the Drosophila quail gene is required for actin bundle assembly during oogenesis. Verheyen, E. and Cooley, L. Profilin mutations disrupt multiple actin-dependent processes during Drosophila development. L. Drosophila kelch is an oligomeric ring canal actin organizer. J. Cell Biol.