Control of cell division and cell differentiation by deoxynucleotides in the early embryo of Xenopus laevis.

It is proposed that the deoxyriboside triphosphates present in the egg of Xenopus laevis support the synchronous cell divisions occurring during the earliest phase of embryonic development and that, as long as synchrony prevails, the cells are prevented from undergoing differentiation. This hypothesis has been tested by injecting deoxyribonucleotides into fertilized eggs. The following effects were observed: 1) the duration of synchrony is prolonged, 2) the morphological development is suppressed, an effect which is greatest when four nucleotides are injected together and 3) the synthesis of all kinds of RNA is inhibited, including the mRNA required for differentiation to occur.