EXPRESSION OF FUNCTIONAL BETA-PLATELET-DERIVED GROWTH-FACTOR RECEPTORS ON HEMATOPOIETIC-CELL LINES

The β-type receptor of platelet-derived growth factor (βPDGFR) is a class III transmembrane receptor with tyrosine kinase activity. The βPDGFR gene is located on mouse chromosome 18 close to the c-fms gene which codes for the colony stimulating factor-1 receptor (CSF-1R). We previously reported that in a high percentage of myeloblastic leukemias induced by the Friend helper murine leukemia virus (F-MuLV), proviruses were integrated in the first intron of the c-fms gene leading to an enhanced expression of c-fms mRNA. Since activation by proviral insertion can act at long distance, we studied βPDGF receptor gene expression in murine myeloblastic leukemias. This gene was found to be frequently expressed but the level of βPDGF receptor mRNA was weak and not related to proviral activation. High affinity binding sites were expressed on myeloblastic cells and ligand binding induced cell proliferation. To determine whether βPDGFR expression is a common feature in hematopoietic cells, we tested cell lines belonging to other hematopoietic lineages. We found that multipotent stem and mast cell lines also expressed the βPDGF receptor gene. This suggests that PDGF, known as a mitogen for connective tissue cells, could also play a role in normal hematopoiesis. © 1993 Academic Press Limited.