Transcriptional regulation of the gene encoding human high affinity IgE receptor (Fc epsilon RI) alpha-chain was analyzed. Previously, we reported that GATA-1 and Elf-1 recognition sites were necessary for cell type-specific activation of the alpha-chain gene promoter. More detailed analysis revealed that other transcription factors bound the regions close to the Elf-1 recognition site and there was a more complex mechanism for the regulation of the promoter activity. On the other hand, during a course of studies to find cis-elements over this gene, CAGCTG sequence in the first intron was revealed to serve as an enhancer. A complex composed of USF1 and USF2 activated the human alpha-chain gene expression via this intronic element. Furthermore, we found two novel exons at 18.4 and 12.6kb upstream from the reported first exon and discovered an additional distal promoter.