Embryonal carcinoma and the basement membrane glycoproteins laminin and entactin

The mouse embryonal carcinoma lines PCC4-F and F9 have played important roles in the isolation and characterization of the two ubiquitous basement membrane proteins, laminin and entactin. The contributions of these cells to our work on extracellular matrices are briefly summarized. The in vitro differentiation of PCC4-F gives rise to a multiplicity of cell types. Two of these cell types have been propagated as cell lines. One of these, M1536-B3, synthesizes and deposits copious quantities of extracellular matrix glycoproteins, which led to the initial discovery and characterization of laminin and entactin. In addition, M1536-B3 provides a model system for analyzing the assembly of laminin and the laminin-entactin complex and for manipulating extracellular matrix structure and composition. The other cell line, 4CQ, synthesizes a matrix consisting of fibronectin and entactin. F9 cells differentiate to endodermal cells in response to retinoic acid and dibutyryl cyclic AMP (Strickland and Mahdavi, Cell 15: 393-402, 1978). The differentiated cells synthesize basement membrane components and provided the probes for the cDNA cloning of entactin and the three chains of laminin. The F9 cells have been widely employed to examine the regulation of expression of the laminin and entactin genes.