Gain-of-function screen identifies a role of the Sec61alpha translocon in Drosophila postmitotic neurotoxicity.
To elucidate the intrinsic mechanisms of neurotoxicity induction, including those underlying neural cell death and neurodegeneration, we developed a gain-of-function screen for gene products causing neural cell loss. To identify novel genes with a cell-death-related function in neurons, we screened 4,964 Drosophila GS lines, in which one or two genes from much of the Drosophila genome can be overexpressed. Approximately 0.68% of the GS lines produced phenotypes involving a loss of postmitotic neurons. Of these, we identified and characterized the endd2 gene, which encodes the Drosophila ortholog of Sec61alpha (DSec61alpha), an endoplasmic reticulum protein with protein translocation activity. Ectopic expression of DSec61alpha caused neural cell death accompanied by the accumulation of ubiquitinated proteins, which was mediated by DSec61alpha's translocon activity. This supported our previous observation that the DSec61alpha translocon contributes to expanded polyglutamine-mediated neuronal toxicity, which is also associated with ubiquitinated protein accumulation. These data suggest that the translocon may be a novel component of neural cell death and degeneration pathways. Our approach can be used to identify potential neurotoxic factors within the whole genome, which will increase our understanding of the molecular mechanisms of various types of cell death, including those associated with human neurodegenerative diseases.
Kanuka
Hirotaka
H
Department of Genetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Hiratou
Tetsuo
T
Igaki
Tatsushi
T
Kanda
Hiroshi
H
Kuranaga
Erina
E
Sawamoto
Kazunobu
K
Aigaki
Toshiro
T
Okano
Hideyuki
H
Miura
Masayuki
M
D000818:Animals; D016923:Cell Death; D002460:Cell Line; D004330:Drosophila / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005123:Eye / Q000166:cytology; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins; D008938:Mitosis; D008954:Models, Biological; D016296:Mutagenesis; D009474:Neurons / Q000166:cytology*; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology; D021381:Protein Transport; D000069816:SEC Translocation Channels; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics
D029721:Drosophila Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; C499383:SEC61 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C506916:Sec61alpha protein, Drosophila