Figure 3.

Whole-mount in situ immunolocalization of Yl in wild-type oocytes. (A) Whole-mount in situ immunolocalization shows that the Yl protein is expressed in the previtellogenic stages. Expression is uniform in the stage 1–5 oocytes. Inset, Protein levels in the stage 2 chamber are highest in the oocyte, but lower levels are apparent in the nurse cells just adjacent and connected to the oocyte via ring canals. (B) In a stage 7 chamber, before vitellogenesis has begun, the receptor is distributed throughout the oocyte. (C) A stage 9 chamber, where vitellogenin is being accumulated, shows Yl enrichment at the cortex of the oocyte. (D) By the end of stage 10, the protein appears to be mostly cortically localized. (E) Df(1)g/Df(1)KA9 yl null controls. Bar, 10 μm.