Missense mutation in the tubulin-specific chaperone E (Tbce) gene in the mouse mutant progressive motor neuronopathy, a model of human motoneuron disease.
Progressive motor neuronopathy (pmn) mutant mice have been widely used as a model for human motoneuron disease. Mice that are homozygous for the pmn gene defect appear healthy at birth but develop progressive motoneuron disease, resulting in severe skeletal muscle weakness and respiratory failure by postnatal week 3. The disease starts at the motor endplates, and then leads to axonal loss and finally to apoptosis of the corresponding cell bodies. We localized the genetic defect in pmn mice to a missense mutation in the tubulin-specific chaperone E (Tbce) gene on mouse chromosome 13. The human orthologue maps to chromosome 1q42.3. The Tbce gene encodes a protein (cofactor E) that is essential for the formation of primary alpha-tubulin and beta-tubulin heterodimeric complexes. Isolated motoneurons from pmn mutant mice exhibit shorter axons and axonal swelling with irregularly structured beta-tubulin and tau immunoreactivity. Thus, the pmn gene mutation provides the first genetic evidence that alterations in tubulin assembly lead to retrograde degeneration of motor axons, ultimately resulting in motoneuron cell death.
Bommel
Heike
H
Institute of Clinical Neurobiology, University of Würzburg, 97080 Würzburg, Germany.
Xie
Gang
G
Rossoll
Wilfried
W
Wiese
Stefan
S
Jablonka
Sibylle
S
Boehm
Thomas
T
Sendtner
Michael
M
D000595:Amino Acid Sequence; D000818:Animals; D048429:Cell Size; D002470:Cell Survival; D002878:Chromosomes, Human, Pair 1; D004195:Disease Models, Animal; D004622:Embryo, Mammalian / Q000033:anatomy & histology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016472:Motor Neuron Disease / Q000235:genetics* / Q000378:metabolism; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology; D020125:Mutation, Missense; D010375:Pedigree; D016415:Sequence Alignment
D018832:Molecular Chaperones; C469269:Tbce protein, mouse