Beatson Institute for Cancer Research, Glasgow, U.K.
We report the isolation and complete sequence of the gene encoding the rabbit erythroid-cell-specific 15-lipoxygenase (RBC 15-LOX), containing 14 exons spanning 8.0 kb. The transcription start point was mapped by S1 nuclease-protection experiments and comparison with the sequence of the RBC 15-LOX mRNA, as defined previously by primer extension experiments. The promoter contains a TATA-like motif, but no CCAAT motif in the canonical position, and lies within a 'CpG-rich island'. Functional analysis of the immediate 5'-flanking DNA by transfection experiments shows that a 150 nucleotide (nt) 5' fragment linked to the chloramphenicol acetyltransferase gene acts as a functional promoter in both erythroid and nonerythroid cell lines and responds in an erythroid-specific manner to the enhancer from the Friend murine leukaemia virus long terminal repeat, whereas a 40-nt fragment is inactive. Intron 7 contains eight copies of a 54-nt repeat containing a region with homology to the simian virus 40/immunoglobulin gene enhancers.