Deoxynucleoside inhibition of differentiation in cultured embryonic cells

Abstract

Summary In agreement with previous results obtained on whole embryos we have found that cultured embryonic cells are prevented from undergoing differentiation as long as deoxynucleoside-containing substances are available. Rather, in the presence of such compounds the cells go on dividing at least two times more than the controls. Autoradiographic estimation of the incorporation of uridine in the cell nuclei shows that deoxyribosides suppress RNA synthesis, although less extensively than actinomycin D. Upon the addition of cytosine arabinoside, which prevents de novo synthesis of DNA, the cells stop dividing when they are about four times larger than the controls, but they undergo normal differentiation. These experiments show that the cells must not undergo a specified number of cell divisions before they enter upon cell differentiation.