Differential Expression of Transforming Growth Factor-Î± and Epidermal Growth Factor in Developing Mouse Embryo

Kil, Young Ki; Woo, Jae Hyung; Kim, Kang Ryune; Kim, Soon Ok

Abstract

The distribution of transforming growth factor-Î± (TGF-Î±) and epidermal growth factor (EGF) in developing mouse embryos of gestational age 8 to 15 days was immunohistochemically (ABC method) studied to investigate the differential expression of these growth factors. Paraffin embedded sections were immunostained with antibodies for TGF-Î± and EGF. Staining of TGF-Î± was observed in several organs derived from endoderm, mesoderm and ectoderm in 9-day-old mouse embryos, such as in the heart, optic pit, head mesenchyme, neural tube and primitive gut, and the staining became more intense in 10 to 15-day-old mouse embryos. The staining of EGF was seen in the heart and primitive gut derived from mesoderm and ectoderm respectively, in 9-day-old mouse embryos, but it was observed in other organs as well in 10 to 15-day-old embryos although the intensity was weaker. In the development of heart, immunoreactivity for TGF-Î± was more intense than EGF, which suggests more active involvement of TGF-Î±. In the lung, TGF-Î± staining was observed both in the bronchus and lung bud, whereas EGF staining was seen only the bronchus. In the nervous system, TGF-Î± was expressed more extensively and more intensively than EGF. In the developing skeletal system, TGF-Î± staining was stronger and the expression was observed at earlier stage compared with EGF. These results indicate that the activity of TGF-Î± is more potent than EGF in the development of mouse embryo in general, especially, in the development of mouse heart, nervous system, mesenchyme and skeletal system.