CHANGES IN GENE-EXPRESSION INDUCED BY A PHORBOL DIESTER - EXPRESSION OF IL-2 RECEPTOR, T3, AND T-CELL ANTIGEN RECEPTOR

Phorbol esters cause an apparent differentiation of human T leukemic cell lines. It was shown previously that TPA induces the expression of the interleukin 2 (IL 2) receptor and the T3 complex on some T cell lines, including CCRF-CEM. We demonstrate that expression of the IL 2 receptor correlated with an induction of the 3.5 and 1.5 kb IL 2 receptor mRNA. In addition, the TPA-induced expression of the T3 polypeptides was found to be accompanied by induction of a putative T cell antigen receptor heterodimer on CEM cells. This was demonstrated by the co-precipitation of the T cell receptor with T3 from digitonin-solubilized cells. The cells expressed high levels of T3 .delta.- and T cell receptor .beta.-chain mRNA in the absence of TPA. The effect of TPA was to cause a rapid accumulation of T cell receptor .alpha.-chain mRNA. This suggested that the .alpha.-chain gene was rearranged before TPA induction and that expression of the T cell receptor/T3 complex on the cell surface was regulated by the level of .alpha.-chain expression. It was also shown that cloned sublines of CEM cells which expressed different T cell antigen phenotypes differed in their response to TPA.