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Fig. 7. Vent2 mediates β-catenin function. (A) Xenopus embryos were injected with the indicated hhex:luciferase constructs with or without Vent2 RNA (500 pg) in D1 anterior or D4 posterior cells at the 32-cell stage. The bar chart shows the normalized relative luciferase activity at gastrula stage, indicating that Vent2 represses the hhex promoter. (B-D) In situ hybridization of bisected stage-18 embryos with the probes indicated. (E) Injection of Gsk3β RNA (500 pg) in the posterior endoderm repressed vent2 expression. (F) Embryos were injected at the 32-cell stage with Vent2 RNA in anterior D1 cells or in posterior D4 cells with either Gsk3β or Gsk3β plus Vent2, followed by in situ hybridization at stage 18 with hhex, and stage 35 with for1 or pdx1 probes. (G) These data suggest a molecular pathway in which Wnt/β-catenin signaling promotes vent2 expression and Vent2 represses hhex transcription. |
