Department of Physiological Chemistry, Karolinska Institutet, Stockholm, Sweden.
Nucleotide sequences that direct transcription of the human 5-lipoxygenase gene have been examined by ligation to the chloramphenicol acetyltransferase gene and determination of chloramphenicol acetyltransferase activity in transfected HeLa and HL-60 cells. Various lengths of 5'-flanking sequences up to 5.9 kilobase pairs 5' of the transcriptional initiation sites were tested. Two positive and two negative apparent regulatory regions were seen. Part of the promoter sequence (-179 to -56 from ATG), which includes five repeated GC boxes (the putative Sp1 binding sequence) was essential for transcription in both HeLa and HL-60 cells. Gel-shift assays (using the DNA fragment -212 to -88) revealed that the transcriptional factor Sp1 could bind to this region of the 5-lipoxygenase promoter. Furthermore, HL-60 nuclear extracts contained specific nuclear factor(s) binding to 5-lipoxygenase promoter DNA, which could not be detected in HeLa cell nuclear extracts.