Collagen synthesis as a marker for cell type in mouse 3T3 lines

Collagen synthesis was applied as a test of the fibroblastic or endothelial origin of the 3T3 mouse lines. Swiss/3T3 lines and Balb/3T3 (clone A31) were compared with respect to the amounts and types of collagen synthesized. All lines symthesized collagen at relatively high and similar rates. For all lines, 75-90% of the collagen synthesized was type I, and the remainder was type III. There was no evidence for synthesis of type IV collagen. By all these parameters, Swiss and Balb/3T3 lines resemble cultured fibroblasts rather than cultured vascular endothelia.