Effects of cytochalasin B upon microfilaments involved in morphogenesis of salivary epithelium.

Cytochalasin B causes cultured mouse salivary gland epithelium to lose its characteristic shape and to cease undergoing morphogenesis. The drug causes disorganization of the 50 A microfilaments in epithelial cells that are thought to control cell shape because of contractile properties. Upon removal of cytochalasin, epithelia regain normal shape and resume morphogenesis. Exceptionally large bundles of microfilaments appear in such recovered epithelial cells at points where their contractile activity could account for the changes in cell and tissue shape.