Multiple controls for the synthesis of muscle-specific proteins in BC3H1 cells.

Abstract

The regulation of the synthesis of muscle-specific proteins was examined in BC3H1 cells, a smooth muscle-like cell line isolated by Schubert et al. The synthesis of creatine kinase and the acetylcholine receptor appear to be under dual control, a positive control due to cell-cell contact which increases the rate of synthesis of this protein, and a negative signal, elicited by serum components, that decreases the rate of synthesis of these proteins. Induction of muscle-specific proteins in BC3H1 in cells is a reversible process and can be arrested after partial induction has taken place by the addition of serum or high MW protein fraction from serum to these cells. The high MW protein fraction from serum is not by itself mitogenic for BC3H1 cells and cannot be replaceed by a variety of known hormones (mitogenic factors).