Disruption of axonal transport by loss of huntingtin or expression of pathogenic polyQ proteins in Drosophila.
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.
Gunawardena
Shermali
S
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
Her
Lu-Shiun
LS
Brusch
Richard G
RG
Laymon
Robert A
RA
Niesman
Ingrid R
IR
Gordesky-Gold
Beth
B
Sintasath
Louis
L
Bonini
Nancy M
NM
Goldstein
Lawrence S B
LS
D000818:Animals; D030801:Animals, Genetically Modified; D001370:Axonal Transport / Q000502:physiology*; D016923:Cell Death / Q000502:physiology; D004330:Drosophila; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics; D010455:Peptides / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype
D029721:Drosophila Proteins; C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010455:Peptides; C097188:polyglutamine