Cloning, sequencing, and analysis of cDNA encoding bovine granulocyte-colony stimulating factor

Neutrophils play a critical role in defending against bacterial infections. Hematopoietic growth factors are a class of regulatory cytokines that are required for stimulation, proliferation, and differentiation of blood cells. Granulocyte colony stimulating factor (G-CSF) is a cytokine that induces proliferation and maturation of precursor myeloid cells in the bone marrow into fully differentiated neutrophils. G-CSF also modulates the functional activity of mature neutrophils. Treatment with G-CSF significantly enhances neutrophil phagocytic activity and killing of bacteria and fungi. We have isolated and sequenced a cDNA clone encoding bovine G-CSF (bG-CSF) from an endothelial cell cDNA library using primers designed from ovine G-CSF. The full length cDNA is 1460 nucleotides with 585 nucleotides comprising the open reading frame. Sequence analysis shows 95% identity with ovine, 89% with porcine, 85% with human, and 76% with murine G-CSF. The deduced G-CSF protein consists of 174 amino acids with 95% identity to ovine, 86% to porcine, 81% to human, and 71% to murine. The signal peptide of G-CSF is 21 amino acids long which is nine amino acids shorter than that of human and murine G-CSF. RT-PCR analysis shows that neither freshly isolated nor ConA stimulated neutrophils express G-CSF mRNA. Mononuclear cells, however, expressed G-CSF mRNA after 48 h incubation with or without ConA stimulation.