Cloning and expression of a cDNA encoding ovine granulocyte-macrophage colony-stimulating factor

A cDNA encoding ovine granulocyte-macrophage colony-stimulating factor (GM-CSF) has been cloned using the polymerase chain reaction. The nucleotide sequence is approx. 93% identical to the published bovine GM-CSF-encoding sequence, 84% to the human sequence and 73% to the murine sequence. The deduced amino acid sequence of the ovine GM-CSF protein was found to be 80% identical to both the human and bovine proteins and 57% to the murine protein. Transient expression of recombinant ovine GM-CSF in COS-1 cells was obtained and its biological activity investigated in a bone-marrow colony-forming assay. Ovine GM-CSF was found to promote the formation of granulocyte-macrophage colonies as well as eosinophil, neutrophil and monocyte/macrophage colonies, an activity characteristic of GM-CSF in other species. Recombinant human GM-CSF was found to have no proliferative effect on ovine bone-marrow cells.