syndecan changes in quantity , location and structure during development : it appears initially on four-cell embryos ( prior to its known matrix ligands ) , becomes restricted in the pre-implementation embryo to the cells that will form the embryo proper , changes its expression due to epithelial-mesenchymal interactions ( for example , induced in kidney mesenchyme by the ureteric bud ) , and with association of cells with extracellular matrix ( for example , during b-cell differentiation ) , and ultimately , in mature tissues becomes restricted to epithelial tissues .
C0007634
cells
C1511002
b-cell