The transfection of epidermal keratin genes into fibroblasts and simple epithelial cells: evidence for inducing a type I keratin by a type II gene.
Through gene transfection studies, we have discovered that the forced expression of a foreign type II epidermal keratin in fibroblasts can trigger the expression of an endogenous type I epidermal keratin. Both the transfected and the induced proteins participate in the formation of filamentous structures. Interestingly, this regulation appears to be unidirectional: the expression of a transfected type I keratin does not induce type II expression. Rather, nonfilamentous aggregates of type I protein accumulate in the cytoplasm. In contrast, simple epithelial cells transfected with either a type I or a type II epidermal keratin gene do not respond by inducing the expression of a host epidermal keratin. In this case, the foreign protein is incorporated into the endogenous keratin network. These results suggest the possibility that type I keratin expression may be dependent on the accumulation of unpolymerized type II keratin.
D000818:Animals; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism*; D004817:Epidermis; D004848:Epithelium; D005347:Fibroblasts; D006801:Humans; D007382:Intermediate Filaments / Q000378:metabolism* / Q000648:ultrastructure; D007633:Keratins / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D014162:Transfection; D014746:Vimentin / Q000378:metabolism
D014746:Vimentin; D007633:Keratins