Mutation in archain 1, a subunit of COPI coatomer complex, causes diluted coat color and Purkinje cell degeneration

• Published in: PLoS genetics 2010-05, Vol.6 (5), p.e1000956
• Main Authors: Xu, Xinjie, Kedlaya, Rajendra, Higuchi, Hitoshi, Ikeda, Sakae, Justice, Monica J, Setaluri, Vijayasaradhi, Ikeda, Akihiro
• Format: Article
• Language: English
• Subjects: Animals; Animals, Genetically Modified; Biosynthesis; Cell Biology/Cellular Death and Stress Responses; Cell Biology/Membranes and Sorting; Cloning; Cloning, Molecular; Coatomer Protein - genetics; Coatomer Protein - physiology; Colleges & universities; Defects; Dermatology/Pigmentary Disorders; Disease; Ethylnitrosourea - pharmacology; Genetics and Genomics/Animal Genetics; Genetics and Genomics/Disease Models; Genetics and Genomics/Gene Discovery; Genetics and Genomics/Gene Function; Genetics and Genomics/Genetics of Disease; Hair Color; Mice; Mutation; Mutation, Missense; Neurodegeneration; Neurological Disorders/Alzheimer Disease; Neurological Disorders/Movement Disorders; Neurological Disorders/Neurogenetics; Neuroscience/Neural Homeostasis; Neuroscience/Neurobiology of Disease and Regeneration; Pathogenesis; Proteins; Purkinje Cells - pathology; Rodents; Subcellular Fractions - metabolism
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1000956

Intracellular trafficking is critical for delivering molecules and organelles to their proper destinations to carry out normal cellular functions. Disruption of intracellular trafficking has been implicated in the pathogenesis of various neurodegenerative disorders. In addition, a number of genes involved in vesicle/organelle trafficking are also essential for pigmentation, and loss of those genes is often associated with mouse coat-color dilution and human hypopigmentary disorders. Hence, we postulated that screening for mouse mutants with both neurological defects and coat-color dilution will help identify additional factors associated with intracellular trafficking in neuronal cells. In this study, we characterized a mouse mutant with a unique N-ethyl-N-nitrosourea (ENU)-induced mutation, named nur17. nur17 mutant mice exhibit both coat-color dilution and ataxia due to Purkinje cell degeneration in the cerebellum. By positional cloning, we identified that the nur17 mouse carries a T-to-C missense mutation in archain 1 (Arcn1) gene which encodes the delta subunit of the coat protein I (COPI) complex required for intracellular trafficking. Consistent with this function, we found that intracellular trafficking is disrupted in nur17 melanocytes. Moreover, the nur17 mutation leads to common characteristics of neurodegenerative disorders such as abnormal protein accumulation, ER stress, and neurofibrillary tangles. Our study documents for the first time the physiological consequences of the impairment of the ARCN1 function in the whole animal and demonstrates a direct association between ARCN1 and neurodegeneration.