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Fig. 4. pPGCs with or without XVLG1 protein in asMO-injected, and Xdsg-3 asMO and Xdsg mRNA coinjected embryos. XVLG1 protein in the perinuclear region of pPGCs is represented by the fluorescence of Cy3 (red), due to immunostaining. Cells derived from the injected GPBC are labeled with FDL (green). The asMO injected and the stage examined are labeled on the panels. Scale bar is 50 μm. (A) All endoderm cells in an embryo are stained with FDL. (A′) Same section as in panel A. Given that the perinuclear cytoplasm of a cell (arrow) is stained with Cy3, it can be concluded as a pPGC. The nucleus seems to be empty. (A′) Merged image of panels A and A′. The pPGC (arrow) is stained with both FDL and Cy3. (B) A pPGC having a granular cytoplasm in the vicinity of the nucleus (arrow) in the endoderm cell mass. (B′) Same section as in panel B. The endoderm cells in the upper part, including the pPGC (arrow) are stained with FDL and those derived from an uninjected cell in the lower part of the right-hand corner are unstained. (B′) Same section in panel B. The perinuclear region of the pPGC (arrow) is weakly stained due to the injection of the asMO. (C) FDL-labeled cell (arrow) is located in the lateral part of the endoderm cell mass in a transverse section. The nucleus and the perinuclear region of the cell are heavily stained. (C′) Same section as in panel C. The perinuclear region of the cell (arrow) and of another cell (arrowhead) in a more dorsal part is heavily stained with Cy3, indicating that they are definitely pPGCs. (C′) Merged image of panels C and C′. One pPGC stained with both FDL and Cy3 (arrow) and the other with Cy3 only (arrowhead) were derived from the asMO-injected and uninjected GPBCs, respectively. The top and bottom are the dorsal and ventral sides, respectively. (D) A pPGC having a granular cytoplasm in the perinuclear region (arrow) is seen in a central part of the endoderm cell mass of a transverse section of an embryo. (D′) Same section as in panel D. The nucleus and its vicinity of the pPGC (arrow) are heavily stained with FDL. (D′) Same section as in panel D. The perinuclear region of these cells (arrows) is not stained with Cy3 because of the scant or complete absence of XVLG1 protein following injection of the asMO. (E) Two cells (arrow and arrowhead), which are obviously different in morphological features from the endoderm cells with many yolk platelets inside at the lower part of this figure, are situated in the uppermost dorsal part of the endoderm cell mass of a transverse section of an embryo. da: dorsal aorta, n: notochord, s: somite. (E′) Same section as in panel E. One of the two cells, being stained with FDL (arrow), is derived from the coinjected GPBC. (E′) Same section as in panel E. The perinuclear region of the FDL-labeled (arrow) and unlabeled (arrowhead) cells are stained with Cy3. These two cells were defined as pPGCs, owing to the presence of XVLG1 protein in the perinuclear region. |
