Progressive cerebellar, auditory, and esophageal dysfunction caused by targeted disruption of the frizzled-4 gene.
Wnt signaling has been implicated in the control of cell proliferation and in synapse formation during neural development, and these actions are presumed to be mediated by frizzled receptors. In this paper we report the phenotype of mice carrying a targeted deletion of the frizzled-4 (fz4) gene. fz4(-/-) mice exhibit three distinct defects: (1) progressive cerebellar degeneration associated with severe ataxia, (2) absence of a skeletal muscle sheath around the lower esophagus associated with progressive esophageal distension and dysfunction, and (3) progressive deafness caused by a defect in the peripheral auditory system unaccompanied by loss of hair cells or other auditory neurons. As assayed using a lacZ knock-in reporter, fz4 is widely expressed within the CNS. In particular, fz4 is expressed in cerebellar Purkinje cells, esophageal skeletal muscle, and cochlear inner hair cells, and the absence of Fz4 in these cells is presumed to account for the fz4(-/-) phenotype. In contrast to the early cell proliferation and patterning effects classically ascribed to Wnts, the auditory and cerebellar phenotypes of fz4(-/-) mice implicate Frizzled signaling in maintaining the viability and integrity of the nervous system in later life.
Wang
Y
Y
Department of Molecular Biology and Genetics, Division of Comparative Medicine, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Huso
D
D
Cahill
H
H
Ryugo
D
D
Nathans
J
J
D000483:Alleles; D000818:Animals; D002526:Cerebellar Diseases / Q000150:complications / Q000235:genetics* / Q000503:physiopathology; D002531:Cerebellum / Q000473:pathology; D004935:Esophageal Diseases / Q000150:complications / Q000235:genetics* / Q000503:physiopathology; D004947:Esophagus / Q000002:abnormalities / Q000473:pathology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000235:genetics; D051157:Frizzled Receptors; D018390:Gene Targeting; D017930:Genes, Reporter; D006130:Growth Disorders / Q000150:complications / Q000235:genetics; D006200:Hair Color / Q000235:genetics; D006319:Hearing Loss, Sensorineural / Q000150:complications / Q000235:genetics* / Q000503:physiopathology; D006579:Heterozygote; D006720:Homozygote; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007794:Lameness, Animal / Q000209:etiology / Q000503:physiopathology; D051379:Mice; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000473:pathology; D009928:Organ Specificity; D010641:Phenotype; D011187:Posture; D011506:Proteins / Q000235:genetics*; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled
D051157:Frizzled Receptors; C498581:Fzd4 protein, mouse; D011506:Proteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled