Figure 3.
Oskar Is Required for the Efficient Recruitment of the Microtubule Plus Ends to the Posterior Pole
(A–C) Wild-type: the plus-end marker, Kin:β-GAL, localizes to the posterior pole of the oocyte at stage 9 ([A], red in [C]) and colocalizes with Staufen ([B], green in [C]).
(D–E) osk54/Df: The posterior localization of Kin:β-GAL ([D], red in [F]) and Staufen ([E], green in [F]) is strongly reduced in an oskar protein-null mutant.
(G–I) A nonrecombinant btz2/+ egg chamber from a germline clone experiment, showing a robust localization of Kin:β-GAL ([G], red in [I]) and Staufen ([H], blue in [I]) to the posterior pole. GFP staining is shown in green in the merged image (I) and marks the nonrecombinant wild-type cells. The signal in the nurse cells indicates that this is not a germline clone.
(J–L) A btz2 germline clone marked by the loss of GFP (green in [L]) from the same experiment as in (G)–(I). Kin:β-GAL (J) is barely detectable at the posterior of the oocyte, whereas Staufen (K) is not localized to the posterior pole, and accumulates at the anterior of the oocyte and diffusely around the oocyte cortex, consistent with the complete absence of oskar mRNA localization to the posterior pole in this mutant.
(M–O) A Khc27 germline clone stained as above. Kin:β-GAL (M) is only very weakly localized to the posterior, whereas Staufen (O) fails to localize there and is mislocalized to the oocyte anterior-lateral cortex, where oskar mRNA is detected in Khc27 mutants. Also note the misplacement of the oocyte nucleus, labeled with the asterisk; this misplacement reflects the requirement for Kinesin in nuclear anchoring 28, 29, 38.