Molecular cloning and characterization of a cDNA for human granulocyte colony-stimulating factor (G-CSF) from a glioblastoma multiforme cell line and localization of the G-CSF gene to chromosome band 17q21

The conditioned media (CM) of the glioblastoma multiforme cell line, U87 MG, contains abundant granulocyte colony-stimulating factor (G-CSF) activity (Tweardy et al., 1987). An oligonucleotide encoding the amino acids -11 to -4 of G-CSF detected a single abundant G-CSF mRNA of 1.6 kilobases (Kb) produced by U87 MG cells. Screening of a U87 MG cDNA library with the oligonucleotide identified cDNA clones of 1.3-1.4 Kb. Sequencing of one clone (pG-CSF6) confirmed that it encoded G-CSF and was derived from G-CSFb mRNA encoding a protein with a three amino acid deletion at positions 36-38. Only a single base substitution was observed at the third position of the codon for leu 152 indicating that G-CSF is highly conserved in cells of widely different origin. Somatic cell hybridization studies and chromosomal in situ hybridization localized the G-CSF gene to the long arm of chromosome 17 in band 17q21, proximal to the 17q breakpoint characteristic of acute promyelocytic leukemia.