Fig. 6. Knockdown of integrin v in integrin-β1-null endoderm cells blocks vitronectin-induced FA formation, GATA4 nuclear translocation and laminin synthesis. (A) Integrin-β1-null ES cells were infected with retrovirus expressing short hairpin RNAs (shRNAs) targeting mouse integrin v. Stable cell lines were established by puromycin selection. Western blots show that transduction of shRNA1 and shRNA4 inhibits the expression of integrin v but not that of integrin 5. (B,C) Integrin-β1-null endoderm cells stably expressing integrin-v shRNA or control vector pSM2 were cultured on vitronectin for 2 days. The cells were fixed and immunostained for integrin β3, paxillin, GATA4 and laminin 1. Nuclei were counterstained with DAPI. GATA4 (red) is mainly localized to the nucleus (purple when merged with DAPI staining) in control cells (arrowheads). By contrast, it is distributed primarily in the cytoplasm in integrin-v knockdown (v KD) cells (arrows). The GATA4 nuclear staining closely correlates with laminin expression (arrows and arrowheads). (D) Cells with positive laminin 1 and nuclear GATA4 staining were counted and plotted.