Development of the inner ear in Splotch mutant mice.
The Splotch mouse, a Pax 3 mutation, represents a model of Waardenburg syndrome I. We show that the homozygous Splotch mutation (Sp(2H)) is associated with severe defects that prevent the formation of the cochlea and vestibulo-cochlear ganglion. To clarify the role of Pax 3 in inner ear formation, we examined the expression of polysialic acid (PSA) associated with neural cell adhesion molecule (NCAM). In accordance with the occurrence of phenotypic abnormalities, PSA NCAM was expressed early in otocyst development in the otic epithelium and the vestibulo-cochlear anlage. During the period of vestibular and cochlear ganglia formation, PSA NCAM expression was decreased. In the late phase of embryonic development, the expression of calcium binding proteins (S100) in the vestibulo-cochlear ganglion was also decreased. Minor differences in S100 immunostaining were found postnatally between the cochleas of heterozygous and wild type animals.
Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic. bucki@biomed.cas.cz
Daniela
D
Buckiová
Josef
J
Syka
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D007758:Ear, Inner / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling; D051379:Mice; D008817:Mice, Mutant Strains / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism; D009154:Mutation; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D009418:S100 Proteins / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D039842:Neural Cell Adhesion Molecule L1; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D009418:S100 Proteins; D012794:Sialic Acids; D014157:Transcription Factors; C103469:polysialyl neural cell adhesion molecule; C068686:Pax3 protein, mouse