Abstract
The effects of tunicamycin, a specific inhibitor of lipid-carrier dependent glycosylation of protein, on the proliferation, adhesion, and differentiation of freshly liberated chondrocytes from chick embryos were studied in clonal cell cultures. Incubation of cells with a high dose of tunicamycin (more than 30 ng/ml) caused complete inhibition of cell division. When tunicamycin was removed after a 5-day exposure in culture, cells immediately started to divide synchronously. The cloning efficiency was higher, and colony size was more regular than in the control culture. Tunicamycin interferred with the adhesion of the cells to the plastic substratum at a low dose (less than 3 ng/ml), and the number of attached cells decreased as the concentration of tunicamycin increased. However, at a higher dose (more than 30 ng/ml), all the cells adhered to the substratum. Different mechanisms of cell adhesion may operate for low and high does of tunicamycin. Formation of the cartilage matrix was not inhibited in so far as the cells proliferated to form colonies.
