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FIG. 4.Sections through the mouth region of embryos stained for Xbap [cc: now called nkx3-1]mRNA (A) or gsc mRNA (A, B, C, and F). Horizontal sections are oriented with anterior at the top. Transverse sections have ventral to the bottom. The positions of the cement gland (cg) and the oral cavity (oc) within the sections are indicated. All sections were photographed at 1001 magnification except C, which is 4001. (A) Transverse section through a double-stained stage 37 embryo. Xbap staining is blue and gsc staining is purple. Both sequences are expressed ventrolat- eral to the oral cavity with Xbap occupying a more lateral position. (B) Horizontal section through the a stage 37 embryo showing Xbap and gsc expression anterior to the oral cavity. Xbap staining marks more lateral tissues. (C) Magnified view of the section shown in B. Notice that the Xbap and gsc staining regions closely abut and appear to overlap in a small area (gray region). (D) Transverse section through the middle of the oral cavity of a stage 37 embryo stained for Xbap sequences alone. Intense Xbap staining is restricted to a small region of tissue lateral to the oral cavity. (E) Transverse section through the posterior of the oral cavity of a stage 37 embryo stained for Xbap alone. A narrow region of Xbap expression is located ventral to the oral cavity, while fainter staining extends upward along the edges of the cavity. (F) Transverse section through the posterior of the oral cavity of a stage 37 embryo stained for gsc alone. Notice that the domain of gsc expression is broader than the Xbap expression shown in E. |
