Transcriptional regulation of RANTES expression in T lymphocytes

We first identified the RANTES chemokine as part of a search for genes expressed by T lymphocytes 'late', 3-5 days, after T-cell activation. The kinetics of expression of RANTES and a small number of other genes are unusual and the mechanism of such delayed expression is unknown. In order to uncover a mechanism for such 'late' expression, we identified and characterized the RANTES promoter and a novel transcription factor regulating RANTES expression in T lymphocytes. RANTES factor of late activated T lymphocytes (RFLAT)-1 is a member of the Kruppel-like family of transcription factors. Like RANTES, RFLAT-1 expression is 'late' after T-cell activation. But, unlike RANTES, regulation of RFLAT-1 expression appears to be translational rather than transcriptional.