Immunofluorescent Localization of Yolk Protein Receptors and Adaptin in Developing Oocytes of Drosophila melanogaster.

Brandy Crum, Matthew Gilbert and David S. Richard, Department of Biology, Susquehanna University, Selinsgrove, PA 17870-1164. To be presented to the Pennsylvania Academy of Science meeting, April, 1999.

During female reproductive development in Drosophila melanogaster, receptor-mediated endocytosis in developing oocytes utilizes non-specific proteins such as clathrin and adaptin and specific yolk protein receptors (YPRs) to sequester yolk proteins (YPs) from the insect hemolymph. Previous studies indicate that clathrin levels may not be a good indicator of the endocytosis of YPs. However, using double-immuno-staining techniques for adaptin and YP-receptor, we show these proteins to co-localize to those nurse cells immediately adjacent to the oocytes. Protein levels in staged ovaries were determined by Western blotting. The production of these proteins in normal reproduction, and during diapause termination indicates that YP-uptake during vitellogenesis is primarily regulated by ecdysteroids and not by the juvenile hormones as previously determined. These observations support a novel mechanism for the endocrine regulation of vitellogenesis and may ultimately provide a basis for novel mechanisms of insect control. (Supported in part by NIH GM/OD54905, to DSR).