Modest loss of peripheral axons, muscle atrophy and formation of brain inclusions in mice with targeted deletion of gigaxonin exon 1.
Mutations in the gigaxonin gene are responsible for giant axonal neuropathy (GAN), a progressive neurodegenerative disorder associated with abnormal accumulations of Intermediate Filaments (IFs). Gigaxonin is the substrate-specific adaptor for a new Cul3-E3-ubiquitin ligase family that promotes the proteasome dependent degradation of its partners MAP1B, MAP8 and tubulin cofactor B. Here, we report the generation of a mouse model with targeted deletion of Gan exon 1 (Gan(Deltaexon1;Deltaexon1)). Analyses of the Gan(Deltaexon1;Deltaexon1) mice revealed increased levels of various IFs proteins in the nervous system and the presence of IFs inclusion bodies in the brain. Despite deficiency of full length gigaxonin, the Gan(Deltaexon1;Deltaexon1) mice do not develop overt neurological phenotypes and giant axons reminiscent of the human GAN disease. Nonetheless, at 6 months of age the Gan(Deltaexon1;Deltaexon1) mice exhibit a modest hind limb muscle atrophy, a 10% decrease of muscle innervation and a 27% axonal loss in the L5 ventral roots. This new mouse model should provide a useful tool to test potential therapeutic approaches for GAN disease.
Dequen
Florence
F
CHUL Research Centre and Department of Anatomy and Physiology, Laval University, Québec City, Québec, Canada.
Bomont
Pascale
P
Gowing
Geneviève
G
Cleveland
Don W
DW
Julien
Jean-Pierre
JP
D000818:Animals; D001369:Axons / Q000378:metabolism / Q000473:pathology; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D053595:Embryonic Stem Cells; D005091:Exons / Q000235:genetics; D005727:Ganglia, Spinal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D018390:Gene Targeting / Q000379:methods; D002479:Inclusion Bodies / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D007381:Intermediate Filament Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D009133:Muscular Atrophy / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D019636:Neurodegenerative Diseases / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D010523:Peripheral Nervous System Diseases / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D010641:Phenotype; D013126:Spinal Nerve Roots / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D014855:Wallerian Degeneration / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology
D003598:Cytoskeletal Proteins; C501171:Gan protein, mouse; D007381:Intermediate Filament Proteins; D008869:Microtubule-Associated Proteins