Up-regulation of c- myc induces the gene expression of the murine homologues of p34cdc2 and cyclin-dependent kinase-2 in T lymphocytes.

Abstract

The expression and/or up-regulation of several early T cell activation genes is dependent on signals transmitted through the interaction of IL-2 and IL-2R well before entry of the cells into S phase. In these studies, murine G0 T cells activated by immobilized anti-CD3 and subsequently blocked in late G1 expressed normal surface levels and mRNA for IL-2R alpha, IL-2R beta, and transferrin receptor (TfR). However, there was no expression of p34cdc2, and cyclin-dependent kinase (cdk)-2 was not up-regulated even in the presence of exogenous rIL-2. In addition the accumulation of c-myc-specific mRNA and protein was significantly reduced. Pretreatment of G0 T cells with c-myc antisense oligonucleotide effectively reduced the level of specific c-myc protein induced by activation of the cells by immobilized anti-CD3. The presence of antisense c-myc oligonucleotide inhibited the expression of cdc2 and cdk2 without affecting the expression of IL-2R alpha and blocked the activated T cells in the G1 phase. Together these studies demonstrate that c-myc regulates the expression of these cdk and suggest a role for c-myc in the G1/S transition.