Cyclic AMP and Myoblast Differentiation
Cell differentiation in the embryo occurs in at least two distinct stages. The first involves a gradual loss in omnipotence of the cells which become ‘covertly’ committed to a particular developmental path. The second is an expression of this newly acquired commitment, a process involving changes in cell morphology and the appearance of specialised cell products characteristic of the particular cell type. Examination of this second stage in differentiation of cells cultured in vitro has revealed that the extent of expression of the differentiated state depends upon a number of external factors. Manipulation of culture conditions for example can often push cells toward differentiation or to continual proliferation (1) and if initially kept under culture conditions which promote proliferation, cells can often still be made to differentiate when placed in more appropriate culture conditions (2,3). Thus it seems that cells can retain the ‘knowledge’ of their commitment to a particular cell type, the expression of the differentiated state involving a complex interaction between the undifferentiated but committed cells and their environment. It is the nature of this interaction in primary cultures of differentiating chick skeletal muscle cells which is the general concern of the work presented here.
KeywordsAdenylate Cyclase Cell Fusion Adenylate Cyclase Activity Myoblast Differentiation Myoblast Fusion
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