FIGURE 7.

Faster proliferation of h2-calponin-free cells. A, Western blots showed that bone marrow cells isolated from adult wild type (WT) and h2-calponin knock-out (KO) mice had positive and negative, respectively, expression of h2-calponin. B, the rate of bone marrow cell proliferation in L929 cell-conditioned media was examined by Crystal Violet staining and the results showed a significantly faster proliferation of h2-calponin-free bone marrow cells than that of wild type cells. C, Western blots showed that the RAW264.7 mouse macrophage line had lost endogenous h2-calponin expression in contrast to primary mouse peritoneal macrophages. Stable transfective expression of mouse h2-calponin cDNA under the cytomegalovirus promoter produced a significant level of h2-calponin. D, RAW264.7 cells stably transfected with sense or antisense h2-calponin cDNA expression vector and non-transfected control were examined for the rate of cell proliferation as in B. The results demonstrated a significant decrease in the h2-calponin sense cDNA-transfected cells in comparison to that of the antisense-transfected and non-transfected RAW cells. The slightly lower proliferation rate of the antisense cDNA-transfected cells than that of the non-transfected cells reflected the effect of G418 in the culture of the transfected cells. **, p < 0.001.