Figure 1.

Xp24δ₂-GFP transgene expression is specific to Xenopus intermediate pituitary and dependent on background color. (A) Pituitary-specific fluorescence in transgenic Xenopus embryos. Shown are living stage 45 embryos, whereby the arrows indicate the locations of the pituitaries with various levels of transgene expression. Fluorescent pituitaries expressing the transgene fusion product could be detected from stage 25 onwards. Bar, 0.4 mm. (B) Fluorescence is specific to the intermediate pituitary of transgenic Xenopus. Ventrocaudal view on the brain that was lifted to reveal the bright fluorescence caused by the Xp24δ₂-GFP fusion protein and observed in the intermediate lobe (IL), but not in the AL, of the pituitary of a black-adapted transgenic frog of 6 mo. Bar, 0.5 mm. (C) Fluorescence in the intermediate lobe of black-(BA) and white- (WA) adapted transgenic (tr) Xenopus. Ventrocaudal view with the anterior part of the pituitary removed. Bar, 0.5 mm. (D) Western blot analysis of p24δ protein expression in the NIL and AL of black-adapted wild-type (wt) and transgenic (tr) Xenopus. (E) Western blot analysis of p24δ protein expression in the NIL of black- and white-adapted wild-type and transgenic Xenopus using the p24δ₁/-δ₂ antibody mix. (F) Newly synthesized proteins produced in NILs of BA and WA wild-type and transgenic Xenopus. NILs were pulse labeled for 1 h, part of the total cell lysates was analyzed directly on SDS-PAGE, and radiolabeled proteins were visualized by fluorography.