title: Gain-of-function screen identifies a role of the Sec61alpha translocon in Drosophila postmitotic neurotoxicity.
abstract: 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.
authors.affiliation: Department of Genetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Kanuka
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Hiratou
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Igaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kanda
authors.forename: Erina
authors.initials: E
authors.lastname: Kuranaga
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Sawamoto
authors.forename: Toshiro
authors.initials: T
authors.lastname: Aigaki
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okano
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miura
mesh_terms: 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
chemical_list: 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