Figure 8.

Stable transfection of 3T3 fibroblasts with α-SMA cDNA enhances collagen gel contraction. 3T3 fibroblasts were stably transfected with VSV-G–tagged α-SMA, α-cardiac, and γ-cytoplasmic actin cDNA, respectively, cloned for different VSV-G-tag expression levels and grown in attached collagen gels. Contraction of released collagen gels was normalized to wild-type 3T3 fibroblast contraction. With increasing expression levels, α-SMA–transfected 3T3 fibroblast (▴, continuous line) contracted significantly more than 3T3 fibroblasts transfected with α-cardiac (♦, dashed line) and γ-cytoplasmic actin (●, dotted line). Each data point represents mean collagen lattice contraction of one clone, calculated from three independent experiments. R² values indicate the correlation between VSV-G-tag expression levels and contraction.