The gene encoding interleukin-3 receptor is located in the pseudoautosomal region (PAR) at the end of the short arm of the X and Y chromosomes. The IL-3R alpha chain gene contains twelve exons and eleven introns that span an area of approximately 40 Kb. It is positioned near (190 Kbp) to the gene encoding for GM-CSFR alpha chain. Both the IL-3R alpha and GM-CSFR alpha genes display a similar structural organization, suggesting a common evolutionary origin for both genes.

At the level of the hematopoietic system IL-3R alpha expression was described on bone marrow CD34+ cells (including primitive multipotential and committed progenitors), granulocytes, monocytes/macrophages, megakaryocytes and B-lymphocytes. Although the IL-3R alpha is expressed on the large majority of progenitor cells, it does not seem to be expressed on the stem cell fraction. The large majority of CD34+ cells possess IL-3R alpha, but its expression is lost during the initial steps of erythroid differentiation, while its expression is maintained up to terminal stages of granulo-monocytic differentiation. The IL-3R alpha is also a distinctive marker of the "lymphoid" dendritic cells present in peripheral blood. IL-3R alpha expression has also been described in several cell types outside the hemopoeitic system, including endothelial cells, fibroblasts and smooth muscle cells.

functional mature IL-3R alpha is located at the level of the plasma membrane where it forms a molecular complex with the IL-3R beta chain.

IL-3R alpha function can be defined by the activity of its ligand interleukin-3. IL-3 is a multipotent cytokine that promotes the development of hemopoietic progenitors into cells of the erythroid, myeloid and lymphoid lineages. In in vitro colony forming assays IL-3 supports the colony formation by virtually all types of hemopoeitic progenitors, including CFU-GEMM, CFU-GM, CFU-G, CFU-M, CFU-Mk, CFU-E and BFU-E.

No mutations of the IL-3Ra gene have been reported in hematological and non hematological human malignancies. Elevated IL-3Ra expression has been reported in about 45% of patients with acute myeloid leukemia and in 40% of patients with acute B lymphoid leukemia. An high IL-3Ra expression has been reported also in hairy cell leukemia.