human genomic library the clone was found to extend 809 base pairs bp upstream of the translation start site of the tnf r a 1 16 kb nhei psti fragment of this clone was subcloned and several deletion constructs thereof prepared the 1 16 kb fragment has promoter activity shown by its ability to drive effective expression of the cat reporter gene in both human hela cells and mouse a9 cells deletion constructs of this clone showed that promoter activity was confined to a 178 bp bglii ecori fragment which included most of the transcription start points further analysis showed that a minimal promoter of 69 bp still exhibits activity s1 nuclease digestion analysis of the rna of hela and u 937 cells with dna probes revealed in both cell lines multiple start sites of transcription the locations of these start sites were identical with all probes used it was found that the promoter sequence according to the present invention resembles promoters of house keeping genes e g the hypoxanthene phosphoribosyltransferase 61 the egf receptor 62 the ngf receptor 60 or the p55 interleukin 1 receptor 63 it is devoid of a tata box and of a ccaat motif and is relatively rich in g and c residues in.