Chromosomal gene organization of the human granulocyte colony-stimulating factor receptor

The human chromosomal gene for the granulocyte CSF (G-CSF) receptor was molecularly cloned from a human gene library. The gene is about 16.5 kb long, and present in a single copy per haploid human genome. The human G-CSF receptor gene consists of 17 exons, and the sequences of exons are completely identical to those of cDNAs isolated from human U-937 myeloid leukemia or placenta cDNA libraries. The G-CSF receptor can be subdivided into several regions: an Ig-like domain, a cytokine receptor homologous domain, three fibronectin type III domains, a transmembrane domain, and a cytoplasmic region. Exons 3-17 code for the G-CSF receptor protein, and each subdomain of the receptor is encoded by a set of exons. Primer extension analysis of the G-CSF receptor mRNA identified major and minor transcription start sites. There is no canonical "TATA" box upstream of the CAP site. About 110 nucleotides upstream of the transcription initiation site of the gene, there is an element of 18 nucleotides that is homologous to the sequences found in the promoter of human myeloperoxidase and neutrophil elastase genes.