To determine the ability of antibodies to provide protection from Ebola viruses, monoclonal antibodies (mAbs) to the Ebola glycoprotein were generated and evaluated for efficacy. We identified several protective mAbs directed toward five unique epitopes on Ebola glycoprotein. One of the epitopes is conserved among all Ebola viruses that are known to be pathogenic for humans. Some protective mAbs were also effective therapeutically when administered to mice 2 days after exposure to lethal Ebola virus. The identification of protective mAbs has important implications for developing vaccines and therapies for Ebola virus.

The ataxia (ax J ) mutation is a spontaneous recessive mutation that results in reduced expression of ubiquitinspecific protease 14, Usp14. Mice homozygous for the ax J mutation are retarded for growth and exhibit several behavioral disorders, including a resting tremor and hindlimb paralysis. Although pathological defects appear to be limited to the central nervous system, reduction of Usp14 expression was widespread in the ax J mice. Usp14 co-fractionated with proteasomes isolated from livers and brains of wildtype mice. Proteasomes isolated from the ax J brains still possessed deubiquitinating activity and were functionally competent to hydrolyze 20S proteasomal substrates in vitro. However, the levels of monomeric ubiquitin were reduced approximately 35% in most of the ax J tissues examined.These results indicate that Usp14 functions to maintain the cellular levels of monomeric ubiquitin in mammalian cells, and that alterations in the levels of ubiquitin may contribute to neurological disease. Keywords: ataxia, mutation, neurological, proteasome, ubiquitin, ubiquitin-specific protease 14. . These disorders are associated with changes in protein degradation that are manifested through the production of protein aggregates. However, it is unclear whether these alterations in the UPS are the primary cause or a secondary consequence of these disorders. Our recent studies on ataxia (ax J ) mice indicate that primary alterations in the UPS can lead to neurological dysfunction (Wilson et al. 2002). The ax J mutation is a spontaneously arising recessive neurological mutation (D'Amato and Hicks 1965). The ax J mice suffer from progressive motor system abnormalities that first appear as a resting tremor when the mice are 2-3 weeks old. At 4 weeks of age, ax J mice exhibit severe hind muscle wasting and ataxia. These mice are completely immobile by 6 weeks of age and death occurs at about 8 weeks of age. The neurological phenotypes observed in the ax J mice are the result of a genetic lesion in the gene encoding the deubiquitinating enzyme Usp14 (Wilson et al. 2002). The insertion of an intracisternal A-particle into intron 5 of Usp14 reduces the expression of Usp14 in the ax J mice to only 5-10% of the levels found in wild-type mice, indicating that the ax J mutation represents a hypomorphic allele of Usp14. A better understanding of the deficiencies in the ax J mice, and in other mice that harbor mutations in the UPS, should therefore provide valuable insights into how the UPS functions in the nervous system and how alterations in these pathways lead to disease.

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Dysfunction of the ubiquitin proteasome system (UPS) has been implicated in the pathogenesis of many neurological diseases, includingAlzheimer's, spinocerebellar ataxia, and several motor neuron diseases. Recent research indicates that changes in synaptic transmission may play a critical role in the progression of neurological disease; however, the mechanisms by which the UPS regulates synaptic structure and function have not been well characterized. In this report, we show that Usp14 is indispensable for synaptic development and function at neuromuscular junctions (NMJs). Usp14-deficient ax J mice display a resting tremor, a reduction in muscle mass, and notable hindlimb rigidity without any detectable loss of motor neurons. Instead, loss of Usp14 causes developmental defects at motor neuron endplates. Presynaptic defects include phosphorylated neurofilament accumulations, nerve terminal sprouting, and poor arborization of the motor nerve terminals, whereas postsynaptic acetylcholine receptors display immature plaque-like morphology. These structural changes in the NMJ correlated with ubiquitin loss in the spinal cord and sciatic nerve. Further studies demonstrated that the greatest loss of ubiquitin was found in synaptosomal fractions, suggesting that the endplate swellings may be caused by decreased protein turnover at the synapse. Transgenic restoration of Usp14 in the nervous system corrected the levels of monomeric ubiquitin in the motor neuron circuit and the defects that were observed in the motor endplates and muscles of the ax J mice. These data define a critical role for Usp14 at mammalian synapses and suggest a requirement for local ubiquitin recycling by the proteasome to control the development and function of NMJs.