Fig. 6. The ₂ß₁ integrin is important for fibroblast force transmission within 3D collagen networks. (A) Equal numbers of wild type (WT) and integrin ₂-deficient (2^-/-) fibroblasts were seeded within triplicate gels of collagen I. The time course of collagen gel contraction was monitored by photographing the gels at successive time intervals as indicated. Note that gel contraction is delayed for integrin ₂-deficient fibroblasts. (B) The gel diameters were measured at successive time points and used to calculate the gel areas, which are plotted as a percentage of the original area at the onset of the experiment. Each point represents the mean ± s.d. of three independent experiments. (C) The isometric forces generated by wild-type (circles) and integrin ₂-deficient fibroblasts (squares) embedded in tethered collagen lattices were monitored over time as indicated. Each data point represents the mean ± s.d. of four measurements.