RECIPROCAL EXPRESSION OF HUMAN ETS1 AND ETS2 GENES DURING T-CELL ACTIVATION - REGULATORY ROLE FOR THE PROTOONCOGENE ETS1

The expression of the protooncogenes ETS1 and ETS2 has been studied in purified human T cells activated either by cross-linking of the T-cell receptor-CD3 complex on their cell surface or by direct stimulation with phorbol esters and ionomycin. Our results show that resting T cells express high levels of ETS1 mRNA and protein, while expression of ETS2 is undetectable. Upon T-cell activation, ETS2 mRNA and proteins are induced, while ETS1 gene expression decreases to very low levels. Late after stimulation, ETS1 mRNA is reinduced and maintained at a high level, while ETS2 gene expression decreases to undetectable levels. Therefore, it appears that in human T cells, ETS2 gene products are associated with cellular activation and proliferation, while ETS1 gene products are preferentially expressed in a quiescent state.