50/50 PBS/formaldehyde concentrate (37% formaldehyde) for one hour. The PBS/fixative phase was then removed and replaced with methanol and the solution was shaken to induce devitelliniza- tion of the embryos. These were stored overnight in methanol. Embryos were then rehydrated in PBT (PBS+0.2% Tween) and blocked in PBT+10% BSA. Mouse monoclonal anti-alpha-tubulin ‘AA4.3’ (DSHB) and goat-anti-mouse Alexa 488 were used to stain microtubules. Embryos were then stored and visualized in Vectashield mounting medium (Vector Laboratories). Immunoflourescent labeling of lipid droplets was performed in whole fixed embryos. Embryos were dechorionated in 50% bleach, rinsed in water, and then fixed for 40 minutes in a 50/ 50 mix of heptane and 10% Formalin solution (3.7% formalde- hyde). Embryos were filtered out of fixative with a nylon mesh and then hand de-vitellinized in a dish of PBS+1% BSA. BicD immunoflouresnce was accomplished with the mouse monoclonal anti-BicD antibody 4C2 (DSHB) at 1:500 and a goat-anti-mouse Alexa 488 conjugated secondary antibody (Invitrogen) at 1:1000. Lipid droplets were identified using either a 12 mg/mL Nile Red solution or by using the lipid droplet specific rabbit polyclonal LSD2-3b at 1:500 and a goat-anti-rabbit Alexa 568 at 1:1000 as the secondary. All blocking and incubations were done in PBS+10% BSA. Confocal imaging was done on a LSM 510 Meta laser scanning microscope (Zeiss). Sequencing of BicDPA66 Genomic DNA was obtained from sterile PA66 homozygote female flies by extraction, phenol/chloroform purifiction, and then References 1. Mohler J, Wieschaus EF (1985) Bicaudal mutations of Drosophila melanogaster: alteration of blastoderm cell fate. Cold Spring Harb Symp Quant Biol 50: 105–111. 2. Wharton RP, Struhl G (1989) Structure of the Drosophila BicaudalD protein and its role in localizing the the posterior determinant nanos. 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