Fig. 7. Ssdp1 acts as a coactivator component of a Lim1-Ldb1-Ssdp1 complex. (A) E8.0 Lim1-lacZ knock-in embryo stained for ß-galactosidase activity. (B) Cross-section of the embryo shown in A; approximate sectioning position is indicated in A. (C) Whole-mount in situ hybridization of Ldb1 in E8.0 embryo. (D) Cross-section of embryo shown in C. Scale bars in C,D: 200 µm. (E) Schematic representation of the effector and the reporter plasmid used in the transfection assay described in F. (F) The fusion protein comprised of the GAL4 DNA-binding domain and Ssdp1 activated reporter gene expression in a dose-dependent manner. (G) Schematic representation of the effectors and a reporter used in the transfection assays described in H and I. (H) Effects of Lim1, Ldb1 and Ssdp1 on the Gsc promoter. (I) Effects of varying Ssdp1 concentration on the activity of Lim1- and Ldb1-mediated reporter gene expression. Values are the means and standard errors of duplicate experiments. (J) A model for the action of Ssdp1. Ssdp1, Ldb1 and Lim1 constitute a ternary complex and regulate genes expressed in the prechordal plate.