par Alexandre, Henri
Référence Wilhelm Roux's Archives of Developmental Biology, 181, 3, page (193-203)
Publication Publié, 1977
Article révisé par les pairs
Résumé : Mouse embryos were collected at the 2 cell stage, cultured in vitro in the presence of 3H deoxyuridine or uridine for 6 or 4 hr and autoradiographed. Deoxyuridine is actively incorporated into the DNA of cleaving mouse embryos indicating the existence of thymidylate synthetase activity at least at the 4 cell stage and presumably already before this. RNAase treatment of embryos squashed on slides shows a weak but obvious incorporation of uridine into DNA of cleaving mouse embryos, from the 4 cell stage onwards; this incorporation is totally inhibited by hydroxyurea. The reduction of ribonucleotides to deoxyribonucleotides is a metabolic pathway already required for cleavage, as shown by hydroxyurea experiments. The second polar body, known to incorporate thymidine, is unable to incorporate either deoxyuridine or uridine.