Fig. 2. mRNA localization and nucleus positioning defects in the sktl mutant oocyte. Wild-type (A,B,E,F,I,J) and sktl^2.3 mutant (C,D,G,H,K,L) Drosophila germline clones. (A-D) grk mRNA distribution. In stage 8 sktl^2.3 mutants, grk mRNA (blue) localizes as in WT (compare C with A). However, in sktl^2.3 stage 10 oocytes, grk mRNA is mislocalized with the nucleus (compare D with B). (E-H) bcd mRNA distribution. In stage 8 sktl^2.3 mutant oocytes, bcd mRNA (blue) localizes as in WT (compare G with E). In stage 10 sktl^2.3 oocytes, bcd mRNA is mislocalized in the form of a cortical ring close to the nucleus (compare H with F). (I-L) osk mRNA localization. In stage 8 sktl^2.3 oocytes, osk mRNA (brown) localizes as in WT (compare K with I). However, during stage 10, osk mRNA does not reach the posterior, unlike in WT (compare L with J), and is mislocalized in the cytoplasm. (M,N) Stage 10 sktl^2.3 mutant egg chamber expressing GFP-Stau (green) and stained for DNA (red). (M) The oocyte nucleus is not anchored to the anterior cortex and is mislocalized in the cytoplasm. (N) Optical cross-section (at the level of the opposing arrowheads in M) showing that the anteriorly detached nucleus remains attached to the lateral cortex of the oocyte. Asterisk, nucleus.