Genetic background alters the severity and onset of neuromuscular disease caused by the loss of ubiquitin-specific protease 14 (usp14)

• Published in: PloS one Vol. 8; no. 12; p. e84042
• Main Authors: Marshall, Andrea G, Watson, Jennifer A, Hallengren, Jada J, Walters, Brandon J, Dobrunz, Lynn E, Francillon, Ludwig, Wilson, Julie A, Phillips, Scott E, Wilson, Scott M
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16.12.2013; Public Library of Science (PLoS)
• Subjects: Aberration; Abnormalities; Alternative Splicing; Amyotrophic lateral sclerosis; Animals; Ataxia; Axons - pathology; Base Sequence; Brain research; Chromosome Mapping; Depletion; Disease Models, Animal; Dystrophy; Enzymes; Ethyl nitrosourea; Gene Expression; Genetic aspects; Hippocampus; Hippocampus - metabolism; Homeostasis - genetics; Humans; Kinases; Laboratory animals; Lethality; Mice; Motor Endplate - metabolism; Motor Endplate - pathology; mRNA; Muscle Fibers, Skeletal - metabolism; Muscle Fibers, Skeletal - pathology; Mutants; Mutation; Nervous system; Nervous system diseases; Neurobiology; Neuromuscular Diseases - enzymology; Neuromuscular Diseases - genetics; Neuromuscular Diseases - mortality; Neuromuscular Junction - metabolism; Neuromuscular Junction - pathology; Neuromuscular junctions; Neuronal Plasticity; Neurophysiology; Neurosciences; Phenotype; Pools; Preservation; Proteases; Protein Subunits - genetics; Proteins; Purkinje Cells - cytology; Purkinje Cells - metabolism; Receptors, Cholinergic - chemistry; Receptors, Cholinergic - genetics; RNA; RNA, Messenger - chemistry; RNA, Messenger - genetics; Severity of Illness Index; Splicing; Synapses - metabolism; Ubiquitin; Ubiquitin - genetics; Ubiquitin - metabolism; Ubiquitin Thiolesterase - deficiency; Ubiquitin Thiolesterase - genetics; Ubiquitin-specific proteinase; Alabama; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0084042

In this study, we identified and characterized an N-ethyl-N-nitrosourea (ENU) induced mutation in Usp14 (nmf375) that leads to adult-onset neurological disease. The nmf375 mutation causes aberrant splicing of Usp14 mRNA, resulting in a 95% reduction in USP14. We previously showed that loss of USP14 in ataxia (ax (J)) mice results in reduced ubiquitin levels, motor endplate disease, Purkinje cell axonal dystrophy and decreased hippocampal paired pulse facilitation (PPF) during the first 4-6 weeks of life, and early postnatal lethality by two months of age. Although the loss of USP14 is comparable between the nmf375 and ax (J) mice, the nmf375 mice did not exhibit these ax (J) developmental abnormalities. However, by 12 weeks of age the nmf375 mutants present with ubiquitin depletion and motor endplate disease, indicating a continual role for USP14-mediated regulation of ubiquitin pools and neuromuscular junction (NMJ) structure in adult mice. The observation that motor endplate disease was only seen after ubiquitin depletion suggests that the preservation of NMJ structure requires the stable maintenance of synaptic ubiquitin pools. Differences in genetic background were shown to affect ubiquitin expression and dramatically alter the phenotypes caused by USP14 deficiency.