Clathrin and adaptin levels in ooctyes from Drosophila melanogaster measured by immunofluorescence and western blotting.

Matthew Gilbert* and David S. Richard. Department of Biology, Susquehanna University, Selinsgrove PA 17870-1164.

During female reproductive development in Drosophila melanogaster, receptor- mediated endocytosis utilizes several non-specific proteins such as clathrin and adaptin which interact with specific receptors to sequester yolk proteins (YPs) from the hemolymph. Using commercial goat anti-clathrin (bovine) primary antibodies with FITC-conjugated rabbit anti-goat IgG second antibodies, and mouse anti-adaptin primary anti bodies with TRITC-conjugated rabbit anti-mouse IgG second antibodies, we show that immunopositive material is localized to developing oocytes. The levels of each protein in homogenates of staged ovaries were determined using Western blotting techniques. Young ovaries (less than 6 hours from adult eclosion) appear to display low levels of clathrin staining and may provide an in vitro model to examine the role of the endocrine system in the control of YP uptake. Ovaries from older females contain oocytes that display more intense clathrin staining than either the younger ovaries or older fully developed stage-14 oocytes. These observations allow us to consider mechanisms by which insect egg development may be regulated by the endocrine system and that ultimately may provide for novel mechanisms of insect control. (Supported in part by NIH GM/OD54905).