Fig. 1. Expression of genes that are deregulated in ß-catenin^-/- embryos, as determined by microarray analysis. (A) Transcriptional changes that occur between E6.0 and E6.5 in wild-type embryos, and comparison with ß-catenin mutants. The expression of 130 genes is downregulated, and expression of 673 genes is upregulated in wild-type embryos between these two stages. In ß-catenin^-/- embryos, most genes are similarly modulated (green; 127 are also downregulated and 591 are also upregulated). A minority of genes are oppositely regulated (red; three genes are downregulated and 82 genes upregulated). (B) Upper panel: dissection scheme for separation of embryonic tissues. X, extra-embryonic tissues (green); VE, visceral endoderm (yellow); EE, embryonic ectoderm including primitive streak region (blue); M, mesoderm (red). Lower panel: assessment of the expression of genes that are known to be expressed in a tissue-specific manner. Pou5f1 is expressed in EE, brachyury (T) in EE and M, Cer1 in VE, and Bmp4 in X (Wilkinson et al., 1990; Rosner et al., 1990; Belo et al., 1997; Lawson et al., 1999). Red, high relative expression; blue, low relative expression; bright area, genes with consistent measurements; dark area, genes with variable or low measurements in certain tissues. (C) Assessment of the tissue specificity of expression of genes that are deregulated in ß-catenin^-/- embryos, as determined by expression profiling. Genes that are deregulated at E6.0 or E6.5 greater than twofold (Change p-Value<0.05) are displayed. Names of selected genes are indicated on the right.