[Demonstration of RNA synthesis during segmentation in the Axolotl embryo].

Study of the incorporation of 3H-uridine in cleaving embryo of Axolotl has shown a nuclear RNA synthesis during the period of synchronous cleavage (6th cycle) as well as after the onset of asynchronous divisions (9th or 10th cycle). In the early development of the Axolotl, the extent of the transcription phase looks to be an essential element of the quantitative control of gene activity.