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Fig. 7. (A,B) The double staining with the anti-CXCR4 and 2L-13 antibodies for a transverse section of embryos. (A) The molecule recognized with the anti-CXCR4 antibody, probably Xenopus CXCR4 (xCXCR4), is mostly detected throughout the cytoplasm of an endoderm cell (arrow) in the dorsal part (cf. Figure 2) of the endoderm cell mass of a stage 33/34 embryo. (A ) The perinuclear cytoplasm of the cell (arrow) in (A) is strongly stained with the 2L-13 antibody, indicating that the cell is a pPGC. (A ) A merged image of (A) and (A ). xCXCR4 is seen throughout the cytoplasm of the pPGC (arrow) while XVLG1 protein recognized with the 2 L-13 antibody is prominent in the perinuclear region. xCXCR4 is not always present in pPGC because it is not detected in a pPGC (arrowhead) situated more dorsally. The top is the dorsal and bottom the ventral side. Bar, 20 μm (B) No endoderm cell in the central part of the endoderm cell mass, including pPGC of a stage 23 embryo, is stained with the anti-CXCR4 antibody. (B ) The perinuclear cytoplasm of five cells (arrows) are stained with the 2L-13 antibody, indicating that they are pPGC. (B ) A merged image of (B) and (B ). xCXCR4 is never observed in the pPGC (arrows) at stages younger than 23. The top is the dorsal and bottom the ventral side. Bar, 50 μm. (C,D) In situ hybridization for polyester wax sections of a stage 28 embryo with riboprobes of xCXCR4. xCXCR4 RNA is prominent in the nucleus of three pPGC (arrows) in the lateral part (cf. Figure 2) of the endoderm cell mass with the antisense probe (C) while it is rarely detected in a pPGC (arrow) on the adjacent section of (C) with the sense probe (D). The pPGC are easily identified by the possession of a granular cytoplasm in the perinuclear region. Bar, 20 μm. |
