The expression pattern of three mast cell specific proteases during mouse development

Mast cell chymases and tryptases are major constituents of mast cell granules exhibiting an intriguing but potentially confusing variety of forms and functions. Thanks to recent genetic and biochemical advances, a clearer picture of phylogenetic and functional relationships in this large group of mammalian enzymes is emerging. While different in vivo and in vitro studies characterize the function of these proteases in adult tissues, only sparse information is available about these enzymes during embryogenesis. In the present study, we followed the expression patterns of three different mast cell proteases - mcpt5 (chymase), mcpt6 and 7 (tryptases) - during the development of the mouse embryo. Using specific probe sets for Northern blot analysis, nested PCR and in situ hybridization we describe the expression patterns of the three proteases in different stages of the developing embryo. Furthermore, we try to localize the expression pattern of the three proteases to a certain region and subset of cells. Based on the spatial and temporal expression patterns of mcpt5, 6 and 7 we hypothesize that these molecules play specific and distinct roles in the prenatal and postnatal stages.