Defective ensheathment of motoric nerves in the Splotch mutant mouse.
Mouse embryos, homozygous for mutations at the Splotch locus, are afflicted with spina bifida and disturbances of neural-crest-derived tissues, e.g. spinal ganglia and pigment cells. The development of Schwann cells is affected in homozygotes to a varying degree along the rostrocaudal axis. In cervical motoric roots, nerves are associated with apparently normal Schwann cells. At the thoracic level, nerve-associated cells become more scarce and resemble the surrounding mesenchymal cells. They are not enveloped by a basal lamina and frequently show wide gaps between neighbouring cells. Lumbar motoric roots are mostly devoid of any associated cells. The Splotch mutant embryo is proposed to be a new animal model for the study of peripheral nerve ensheathment. The implications for Schwann-cell-mediated axon guidance are discussed.
Franz
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Abteilung für Neuroanatomie, Universitäts-Krankenhaus Eppendorf, Hamburg, BRD.
D000818:Animals; D004622:Embryo, Mammalian / Q000294:innervation; D006720:Homozygote; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains / Q000033:anatomy & histology* / Q000235:genetics; D008854:Microscopy, Electron; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure*; D009186:Myelin Sheath / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure*; D009432:Neural Crest / Q000196:embryology / Q000473:pathology; D010641:Phenotype; D012583:Schwann Cells / Q000473:pathology