Interleukin 1 and tumor necrosis factor enhance transcription from the SV40 early promoter in a T cell line

Interleukin 1 (IL 1) and tumor necrosis factor (TNF) increase the expression of a number of T lymphocyte-specific genes in the T-cell hybrid PC60. We show here that human IL 1 alpha and 1 beta, mouse IL 1 alpha and mouse TNF-alpha strongly enhance expression of reporter genes transcribed from the SV40 early promoter in this cell line. We found that IL 1 and TNF each induce up to a 30-fold increase in the rate of transcription, resulting in a proportional increase of mRNA and protein levels. Induction with IL 1 and TNF is detectable after 1 h and reaches a plateau after about 15 h. Removal of these factors from the culture medium results in complete reversion. Induction with IL 1, but not with TNF, can be inhibited with an inhibitor of IL 1 binding. The effects of both factors are not impaired by the protein synthesis inhibitor cycloheximide, suggesting that they stimulate expression from the SV40 early promoter by activation of preexisting transcription factors.