Proliferation in the neural tube of the splotch (<i>Sp</i>) mutant mouse

Abstract

Abstract The length of each period in the cell cycle was determined radioautographically for mesencephilic ventricular cells in splotch normal ( Sp /+;+/+) and abnormal (Sp/Sp) mouse embryos. At ten and 11 days' gestation, the length of the generation time in the abnormal brain was approximately 3.5 hours longer than that in the normal littermates. This overall prolongation was the result of an increase in the DNA‐synthetic (S), mitotic (M), and postmitotic (G 1 ) periods. The increase in the length of mitotis appeared to be responsible for the increased numbers of mitotic figures which characterize this condition. The abnormal brains, however, showed a typical chronological lengthening of the cell cycle of approximately the same magnitude as is the case during normal development of the neural tube.