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Fig. 5. Potential regulation of en-2 by XlPOU 2 in the MHB. (A) Expression pattern of XlPOU 2 by whole-mount in situ hybridization of a stage 24 embryo (dorsal view). XlPOU 2 is expressed predominantly in the MHB (black arrow) and in the pronephros (white arrow). (B) Expression pattern of en-2 by wholemount in situ hybridization of a stage 24 embryo (dorsal view). En-2 is expressed in the MHB. (C) Expression pattern of XlPOU 2 and en-2 by double wholemount in situ hybridization of a stage 24 embryo (dorsal view). XlPOU 2 expression (white arrows), is visualized as the turquoise reaction product of alkaline phosphatase (BCIP). (D) A high magnification view of XlPOU 2 and en-2 co-localized at the MHB (dark purple; magenta-phosphate 1 BCIP). (E,F) VP16-POU-GR injected and dex-treated embryo shows an expansion of the MHB (E; black arrows), while non-dex treated embryo shows normal expression pattern for en-2 (F; white arrows show b-gal staining and an arrow outlined in black indicates the normal boundary of en-2 expression). (G,H) ENG-POU-GR dramatically reduces en-2 expression in the injected and dex-treated embryo (compare G and H; white arrows indicate the b-gal staining and a black arrow show repression; H, an arrow outlined in black indicates the normal boundary of en-2 expression). |
