Effet de l'inhibition spécifique de la réplication de l'ADN par l'aphidicoline sur la différenciation primaire de l'auf de souris en préimplantation.

Aphidicolin inhibits cleavage at every stage of preimplantation of Mouse embryos without affecting compaction. Blastulation is initiated only if the treatment is applied at the late 8-cell stage. It is concluded that the S phase of the 4th cell cycle might be critical for the commitment of the embryo for blastocyst formation. The 4th cycle thus corresponds to a "quantal cell cycle". Moreover, aphidicolin induces premature cavitation which occurs even when the embryos have not yet initiated cytokinesis.