Src expression during murine development

The study examines the distribution of src gene products in mouse embryo ti ssues, to reveal the patterns of expression that may elucidate the potentia l role of the Src family during development. Immunohistochemical analysis d emonstrates that eight members (c-Src, Fyn, Yes, Lyn, Lck, Hck, Fgr and Blk ) within the Src family are expressed early in dividing cells from preimpla ntation stages and remain in many tissues until the late prenatal stages. E xperimental results indicate that Src expression is present prevalently in fetal development in tissues from all three germ layers. For instance, ecto dermal derivatives that displayed Src expression included both nervous syst em and epidermis cells. Meanwhile, mesodermal tissues including chondrocyte s, kidney, gonad, and endoderm-derived tissues, such as from the heart, lun g and intestine, also expressed Src immunoreactivity. In the heart, Src is expressed at embryonic day 8, the time when myocardial contraction begins, and remains throughout the embryonic stage. However, widespread expression becomes restricted to certain cell types with maturation. For example, the Src family is restricted to the epithelial lining and muscular layer in the gastrointestinal ducts during the later stage of embryo growth. This study have observed a slight difference in the progression of the expression and in staining intensity although the overall pattern for the eight Src famil y members is similar. The wide distribution of the Src family in the develo ping mouse tissues implies that many immature cells require these gene prod ucts for signal transduction and possibly for regulating cell survival.