Close Localization of the Genes for GM-CSF and IL3 in Human Genome

Colony-stimulation factors (CSFs), a family of glycoprotein growth factors, have been shown to support clonal proliferation of hematopoietic progenitor cells in vitro [1]. Macrophage-CSF (M-CSF or CSF-1) [2] and granulocyte-CSF (G-CSF) [3] stimulate cells committed to the macrophage and granulocyte lineages respectively, whereas granulocyte-macrophage-CSF (GM-CSF) and interleukin-3 (IL3 or multi-CSF) are capable of stimulating proliferation and differentiation of progenitors along multiple pathways.