Fig. 4. Polarized endocytic activity within the Drosophila oocyte depends on Osk and Grk. (A-C) Distribution of Stau, Rbsn-5, Rab11 and incorporated FM4-64 dye, as indicated, in wild-type (A), osk⁵⁴/Df(3R)^pXT103 (B), and grk^HK36/Df(2L)ED623 (C) oocytes at stages 8 and 10. DNA in all images was visualized by DAPI staining (cyan). Note that signals for Rbsn-5 on lateral cortex were consistently reduced in osk mutant oocytes at stage 8 (B), and that Rab11 failed to localize to the center of grk mutant oocytes (C). We presently do not know why these differences occur. (D-F) Percentages of oocytes showing a posterior accumulation of Rbsn-5 and Rab11 in wild-type (D), osk⁵⁴/Df(3R)p^XT103 (E) and grk^HK36/Df(2L)ED623 (F) oocytes during stages 8-10. Error bars denote the standard deviation from at least three independent experiments. Scale bars: 20 µm.