Schematic representation of the humanIL1Agene and 5′ RACE. Exons are depicted as rectangles, white for untranslated and black for translated region. The transcription start site (TSS1) of IL-1α as investigated by 5′RACE is indicated by an arrow. Positions of cDNA-specific primers are indicated by i (inner primer), o (outer primer), and gs (gene specific). The CpG sites in the promoter (numbered –13 through +1) and intron IV (numbered +17 through +29) of the IL1A gene are numbered relative to the transcription start site and are given in an enlarged representation at bottom. Nucleotide numbers of the enlarged regions are given relative to the transcription start site in the genomic DNA and are indicated above the fragments.