Transforming growth factor-β1 mediates cellular response to DNA damage in situ

Abstract

Transforming growth factor (TGF)-β1 is rapidly activated after ionizing radiation, but its specific role in cellular responses to DNA damage is not known. Here we use Tgfβ1 knockout mice to show that radiation-induced apoptotic response is TGF-β1 dependent in the mammary epithelium, and that both apoptosis and inhibition of proliferation in response to DNA damage decrease as a function of TGF-β1 gene dose in embryonic epithelial tissues. Because apoptosis in these tissues has been shown previously to be p53 dependent, we then examined p53 protein activation. TGF-β1 depletion, by either gene knockout or by using TGF-β neutralizing antibodies, resulted in decreased p53 Ser-18 phosphorylation in irradiated mammary gland. These data indicate that TGF-β1 is essential for rapid p53-mediated cellular responses that mediate cell fate decisions in situ.