Disruption of Axonal Transport by Loss of Huntingtin or Expression of Pathogenic PolyQ Proteins in Drosophila

• Published in: Neuron (Cambridge, Mass.) Mass.), 2003-09, Vol.40 (1), p.25-40
• Main Authors: Gunawardena, Shermali, Her, Lu-Shiun, Brusch, Richard G., Laymon, Robert A., Niesman, Ingrid R., Gordesky-Gold, Beth, Sintasath, Louis, Bonini, Nancy M., Goldstein, Lawrence S.B.
• Format: Article
• Language: English
• Subjects: Animals; Animals, Genetically Modified; Apoptosis; Axonal Transport - physiology; Cell Death - physiology; Cytoskeleton; Defects; Disease; Drosophila; Drosophila Proteins - biosynthesis; Drosophila Proteins - deficiency; Drosophila Proteins - genetics; Female; Gene Expression Regulation - physiology; Genes; Genotype & phenotype; Humans; Huntingtin Protein; Huntington Disease - genetics; Huntington Disease - metabolism; Huntington Disease - pathology; Insects; Male; Nerve Tissue Proteins - biosynthesis; Nerve Tissue Proteins - deficiency; Nerve Tissue Proteins - genetics; Neurodegeneration; Neurons; Nuclear Proteins - biosynthesis; Nuclear Proteins - deficiency; Nuclear Proteins - genetics; Peptides - deficiency; Peptides - genetics; Peptides - metabolism; Phenotype; Proteins; Rodents
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/S0896-6273(03)00594-4

We tested whether proteins implicated in Huntington's and other polyglutamine (polyQ) expansion diseases can cause axonal transport defects. Reduction of Drosophila huntingtin and expression of proteins containing pathogenic polyQ repeats disrupt axonal transport. Pathogenic polyQ proteins accumulate in axonal and nuclear inclusions, titrate soluble motor proteins, and cause neuronal apoptosis and organismal death. Expression of a cytoplasmic polyQ repeat protein causes adult retinal degeneration, axonal blockages in larval neurons, and larval lethality, but not neuronal apoptosis or nuclear inclusions. A nuclear polyQ repeat protein induces neuronal apoptosis and larval lethality but no axonal blockages. We suggest that pathogenic polyQ proteins cause neuronal dysfunction and organismal death by two non-mutually exclusive mechanisms. One mechanism requires nuclear accumulation and induces apoptosis; the other interferes with axonal transport. Thus, disruption of axonal transport by pathogenic polyQ proteins could contribute to early neuropathology in Huntington's and other polyQ expansion diseases.