Expression of the human beta-globin gene in mouse teratocarcinoma cells

We have stably transformed PCC4 and F9 teratocarcinoma stem cells with the human beta-globin gene. The transformed PCC4 cells retained their ability to produce in host mice tumours containing various differentiated tissues. Three of the five clones examined had human beta-globin transcripts, with correct 5' termini; however, some transcripts were also initiated upstream from the natural cap site in two of the three clones. The expression of the human beta-globin gene was maintained when the stem cell phenotype was changed, either into endodermal cell type by retinoic acid treatment of the F9 clones, or into fibroblastic cell type by cell hybridization of transformed PCC4 cells with L fibroblasts. Thus, the human beta-globin gene introduced into early embryonic cells can be expressed constitutively and its expression is maintained when the pattern of gene expression in the cells is changed.