Molecular cloning and expression of woodchuck granulocyte-macrophage colony stimulating factor

Granulocyte-macrophage colony stimulating factor (GM-CSF) has immunoregulat ory and antiviral effects, and may thus be promising for the treatment of c hronic hepatitis B. Using woodchuck hepatitis virus (WHV)-infected woodchuc k as an animal model to test the efficacy and safety of GM-CSF on the thera py of chronic hepatitis B, woodchuck GM-CSF will be require due to the appa rent species-specific activity of GM-CSF. The cDNA of woodchuck GM-CSF was cloned using reverse transcription-polymerase chain reaction (RT-PCR) with primers deriving from highly conserved regions of GM-CSF genes from other s pecies. The deduced amino acids including the signal peptide, is 138 in len gth and its identities to human, murine, canine and bovine GM-CSFs are 63, 49, 63, and 63% respectively. The genomic DNA of woodchuck GM-CSF was also cloned by PCR. Its organization is highly homologous to that of human and m urine GM-CSF genes, consisting of four exons and three introns. Cloned wood chuck GM-CSF was expressed transiently in 293T cells. The recombinant prote in expressed was found to stimulate the growth and differentiation of woodc huck bone marrow cells, indicating the protein expressed by the cloned gene is functional. These results pave the way for future studies on the potent ial role of GM-CSF for the treatment of chronic hepatitis B by using this a nimal model.