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Fig. 3. In situ hybridization to sectioned tissue from oocytes and embryos. Middle and late stage oocytes were oriented during embedding
such that sections cut through the animal-vegetal axis. Early stage oocytes were randomly oriented during embedding. (A) Early stage I-II
oocytes (small arrows) have Xwnt-11 mRNA distributed uniformly in the cytoplasm. Middle stage III-IV oocytes (large arrows) are
beginning to localize Xwnt-11 mRNA at one pole of the oocyte. The germinal vesicle is visible as a dark circle in the middle of each
oocyte. The sections shown in B, C and D are all oriented with the animal pole facing up and the vegetal pole facing down. (B) Late stage
V-VI oocyte shows that Xwnt-11 mRNA is localized to the vegetal cortex and to patches in the vegetal cytoplasm. The germinal vesicle is
in the animal hemisphere. (C) Unfertilized egg shows that Xwnt-11 mRNA is diffusely localized to the vegetal hemisphere. (D) 8-cellstage
embryo shows that Xwnt-11 mRNA remains diffusely localized to the vegetal hemisphere. The horizontal cleavage plane of the
third cell division (arrowheads) confines the mRNA to vegetal blastomeres. |
