Structure of the gene encoding the alpha 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 alpha subunit and a beta subunit shared by garanulocyte-macrophage colony stimulating factor and interleukin 5 receptors. In this paper, we determined the genomic structure of the alpha subunit of the human interleukin 3 receptor, which spans approximately 40 kb and has 12 exons. We found that the genomic structures of the alpha 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 alpha subunit of the interleukin 5 receptor. These results suggest a shared evolutionary pathway of these two genes.