Messenger RNA expression of granulocyte colony-stimulating factor receptor isoforms in the fetus

Granulocyte colony-stimulating factor (G-CSF) is a growth factor known to support the proliferation, differentiation, and survival of cells of the neutrophil lineage. G-CSF affects these cells after binding to its specific receptor, G-CSF-R, which exists in seven isoforms. While information exists about the distribution of these isoforms in hematopoietic cells and placenta, G-CSF-R isoforms on non-hematopoietic fetal tissues have not been described. Using RT-PCR, we analyzed a variety of human fetal tissues ranging from 6 to 18 weeks gestation. Isoforms I and III were present in all tissues, and the expression of isoform III varied with gestational age. The remaining isoforms were variably expressed in relation to tissue type and gestational age. Thus in the human fetus, G-CSF-R isoform I is the predominant form expressed on non-hematopoietic and hematopoietic tissues.