title: The effect of the splotch gene on the parameters of the cell cycle in the brain and spinal cord of mouse embryos.
abstract: The parameters of the cell cycle were determined in 10-day-old mouse embryos, homozygous for the splotch (Sp) gene, by the radioautographic method with H-3-thymidine. Normal embryos (+/+)with a similar genetic environment were used as the control. In the brain and spinal cord of Sp/Sp embryos the mitotic indices were more than twice as high as those in +/+ embryos. The rate of cell proliferation increased identically in both the dorsal and ventral parts of the neural tube. The generation time of the brain and spinal cord cells of Sp/Sp embryos was 8 h and that of normal embryos 9 h. The Sp gene decreased the duration of the S phase 1.5 h (25 percent). In addition, this gene increased the duration of the G(1) phase 0.5 h. The Sp gene evidently acts in the G(1) phase, as a result of which the duration of this phase increases while that of the S phase decreases considerably. This leads to an increase in the rate of cell proliferation and to the development of abnormalities of the CNS of homozygous embryos.
mesh_terms: D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000196:embryology*; D002455:Cell Division; D005260:Female; D005796:Genes; D006720:Homozygote; D008297:Male; D051379:Mice / Q000196:embryology*; D008938:Mitosis; D009154:Mutation; D010858:Pigmentation; D011247:Pregnancy; D013116:Spinal Cord / Q000196:embryology*; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors; D014316:Tritium
chemical_list: D014316:Tritium; D013936:Thymidine