Structure of the gene encoding the α subunit of the human interleukin 3 receptor

Interleukin 3 is a cytokine that stimulates proliferation and differentiation of hematopoietic progenitor cells. Its receptor consists of two subunits, an interleukin 3-specific α subunit and a β subunit shared by garanulocyte-macrophage colony stimulating factor and interleukin 5 receptors. In this paper, we determined the genomic structure of the α subunit of the human interleukin 3 receptor, which spans approximately 40 kb and has 12 exons. We found that the genomic structures of the α subunits of the human interleukin 3 and granulocyte-macrophage colony stimulating factor receptors are very similar. They possess a unique additional intron in the ′C domain′, which is absent in the α subunit of the interleukin 5 receptor. These results suggest a shared evolutionary pathway of these two genes.