Resumen de Receptor protein tyrosine phosphatase m expression as a marker for endothelial cell heterogeneity; analysis of RPTPm gene expression using LacZ knock-in mice
Elianne A. Koop, Susana M. Chuva de Sousa Lopes, Martin Van der Valk, Christine L. Mummery, Hans A. R. Bluyssen, Elles Feiken, Wouter H. Moolenaar, Martijn F.B.G. Gebbink, Emile E. Voest
The receptor-like protein tyrosine phosphatase µ (RPTPµ) belongs to the subfamily of meprin, A5, RPTPµ (MAM) domain-containing RPTPs, which are thought to play an important role in cell-cell adhesion mediated processes. The current study was designed to examine the expression pattern of RPTPµ in mice. We have generated RPTPµ-LacZ knock-in mice that express the ß-galactosidase (LacZ) reporter gene under the control of the RPTPµ promoter. LacZ expression patterns were analysed in embryos and adult mice by whole mount LacZ staining. Analysis of ß-galactosidase activity of heterozygous embryos and adult tissues revealed RPTPµ expression in endothelial cells of arteries and capillaries. In contrast, expression was virtually absent in endothelial cells of veins and in fenestrated endothelial cells in the adult liver and spleen. Moreover, RPTPµ expression was found in endothelial cells from the endocardium and the aorta in embryos, but not in adult mice. In addition to heterogeneous expression in endothelial cells, RPTPµ expression was found in cardiac muscle cells but not in skeletal muscle cells or smooth muscle cells. Expression was also found in Type II pneumonocytes in the lung alveoli and in Purkinje cells and other neurons in the brain. The specific expression of RPTPµ in arterial endothelial cells and in cardiac myocytes suggests that RPTPµ may play a role in the regulation of cardiovascular functions.
