Expression of the hepatocyte growth factor/scatter factor receptor tyrosine kinase is localized to epithelia in the adult mouse.

The met proto-oncogene receptor tyrosine kinase has been identified as a receptor for hepatocyte growth factor (HGF)/scatter factor (SF). HGF/SF is a multifunctional cytokine that stimulates mitogenesis, dissociation, and motility of a broad spectrum of epithelial and endothelial cells in culture, promotes the progression of carcinoma cells to a more invasive phenotype, and acts as a morphogenic factor for tubular epithelia. HGF/SF is predominantly expressed by mesenchymal cells, whereas the met/HGF/SFR is predominantly expressed by epithelial and carcinoma cells in culture. We have shown by Northern analyses that the met/HGF/SFR is expressed in many adult mouse tissues. To elucidate the normal physiologic role for the met/HGF/SFR and the possible pathologic consequences of deregulation of this pathway, we have examined the expression of the met/HGF/SFR in adult mouse tissue by in situ hybridization. We show that the met/HGF/SFR is generally expressed in epithelia, including hepatocytes, epithelial cells that line the proximal and distal convoluted tubules of the kidney, epithelia of stomach, esophagus, uterus, lung and skin, as well as in granulosa cells of developing and mature oocytes. By reverse transcriptase PCR amplification, we show that the HGF/SF gene is expressed at low levels in many of these tissues. Our data support a possible role for the met/HGF/SFR in epithelial cell growth and tissue organization.