XB-IMG-41993
Xenbase Image ID: 41993
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Fig. 1. A 3.8 kb XTcf-4 promoter fragment reflects endogenous XTcf-4 expression. A) Sequence of the XTcf-4 promoter from − 3855 to − 2720 (Acc. No. EU085381). Putative transcription factor binding sites are indicated. B) A 2.7 kb XTcf-4 promoter fragment injected one blastomere of 2-cell stage embryos is active in a mosaic pattern, predominantly in the endoderm. (C) EGFP driven by the 3.8 kb promoter fragment injected one blastomere of 2-cell stage embryos is found exclusively in the midbrain (left) in a similar region as endogenous XTcf-4 mRNA (right). (D) Comparison of 3.8 kb promoter fragment driven EGFP-RNA expression (left) and the localization of endogenous XTcf-4 protein (right). E) Expression of EGFP driven by a 3.8 kb XTcf-4 promoter fragment in transgenic frogs revealed high expression in the brain. The expression domain is found more posteriorly, adjacent to the isthmus, but still in the midbrain as it is typical for XTcf-4 at tadpole stage (see ISH in Fig. 2). F) Activity of different promoter fragments in Xenopus embryos at late neurula (Stage 19) and tailbud (stage 26) stages. Activity of the empty pGL3 vector is set as 1. 500 pg DNA of the indicated XTcf-4 promoter construct was coinjected with 100 pg CMV-β-galactosidase. Given are mean values and standard errors of n > 7. G) Co-transfected en2 represses the − 3773/+501 XTcf-4 promoter construct almost two fold in XTC cells. Mutation of the putative en2 binding site (3773/+501 en2mut) abolishes en2 mediated repression. H) Coinjection of 100 pg en2 mRNA represses the XTcf-4 promoter in Xenopus embryos. Mutation of the putative en2 binding site (3773/+501 en2mut) abolishes en2 mediated repression. Image published in: Koenig SF et al. (2010) Copyright © 2010. Image reproduced with permission of the Publisher, Elsevier B. V.
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