Cytological analysis of the border between the midbrain and cerabellum in wnt-1 gene deficient "swaying" mice

The murine mutation“swaying”is caused by a mutant allele of the Wnt1gene(Wnt1 I D1SWⅡD1)which has a single base pair deletion that terminates translation of the Wnt1 protein，We have analyzed a series of pre and postnatal swaying mice to evaluate the developmental effects of the absence of Wnt1y D1.On embryonic day14(E14)，the cerebellum and midbrain are still absent in the swaying mouse，On postnatal day0(PO)the hemispheres are clearly seen，but the midline fusion to form the vermis does not occur until between P5 and P7。The border between the inferior and superior colliculi in the midbrain does not appear and positional and size abnormalities become recognizable on PO。Meanwhile，the anterior lobes of the cerebellar hemispheres appear to fuse with the midbrain around P5。During P10-P15，laminar abnormalities of the cerebellum become recognizable。Also，from P5，asymmetries in the size of the cerebellar hemispheres appear and are accompanied by asymmetries in the lamination of the inferior olivary nucleus.These findings indicate that the abnormal development in the cerebellum and midbrain of the swaying mouse proceeds in an orderly way and，in particular，indicates that a)abnormal development of the cerebellum is secondary to development of the hemispheres of the hemispheres appear and are accompanied of the cerebellum and the cerebellum of the hemispheres of the cerebelopment of the cerebelopment of the cerebellum of the hemispheres of the the cerebellum and；

The murine mutation "swaying" is caused by a mutant allele of the Wnt1 gene (Wnt1ィイD1SWィエD1) which has a single base pair deletion that terminates translation of the Wnt1 protein, We have analyzed a series of pre and postnatal swaying mice to evaluate the developmental effects of the absence of Wnt1ィイD1SWィエD1. On embryonic day 14(E14), the cerebellum and midbrain are still absent in the swaying mouse, On postnatal day 0 (PO) the hemispheres are clearly seen, but the midline fusion to form the vermis does not occur until between P5 and P7. The border between the inferior and superior colliculi in the midbrain does not appear and positional and size abnormalities become recognizable on PO. Meanwhile, the anterior lobes of the cerebellar hemispheres appear to fuse with the midbrain around P5. During P10-P15, laminar abnormalities of the cerebellum become recognizable. Also, from P5, asymmetries in the size of the cerebellar hemispheres appear and are accompanied by asymmetries in the lamination of the inferior olivary nucleus.These findings indicate that the abnormal development in the cerebellum and midbrain of the swaying mouse proceeds in an orderly way and, in particular, indicates that a) abnormal development of the cerebellum is secondary to development of the midbrain and b) asymmetric development of the inferior olive is secondary to asymmetric development of the cerebellum.