GENOMIC ORGANIZATION AND TRANSCRIPTIONAL REGULATION OF THE RANTES CHEMOKINE GENE

RANTES is a member of a large supergene family of pro-inflammatory cyt okines called CC chemokines that appear to play a fundamental role in inflammatory processes. The RANTES protein causes release of histamine from basophils and is a chemoattractant for CD45RO/CD4+ ''memory'' T lymphocytes, monocytes, and eosinophils. Although expression of RANTES was first thought to be limited to activated T cells, recent data hav e shown that it is produced by a variety of tissue types in response t o specific stimuli. RANTES mRNA is expressed late (3 to 5 days) after activation of resting T cells whereas in fibroblasts, renal epithelial and mesangial cells, RANTES mRNA is quickly up-regulated by TNF-alpha stimulation. In order to gain a better understanding of the molecular mechanisms that regulate expression of the RANTES locus, we have char acterized the RANTES gene and determined a putative promoter region. T he RANTES gene spans approximately 7.1 kb and is composed of three exo ns of 133, 112 and 1075 bases and two introns of approximately 1.4 and 4.4 kb with the position of intron/exon boundaries conserved relative to the other CC chemokine family members. Approximately 1 kb of DNA f rom the immediate 5' upstream region of RANTES was sequenced and found to contain a large number of potential consensus elements for specifi c T cell/hemopoietic, myeloid, muscle, and ubiquitously expressed DNA- binding factors. RANTES-promoter-luciferase gene fusion assays demonst rate high levels of reporter gene activity in a ''mature'' T cell line Hut78, the erythroleukemic cell line HEL, and the rhabdomyosarcoma ce ll line RD, with little or no activity in the ''early'' T cell line Ju rkat, the gammadeltaT cell line PEER, the thymic tumor Molt4, or the p re-erythroid cell line K562. Deletion analysis of the promoter region indicates that different transcriptional mechanisms control expression of RANTES in the various tissues studied.