Modulation of gurken translation by insulin and TOR signaling in Drosophila

Scott B. Ferguson, Malachi A. Blundon, Martha S. Klovstad, Trudi Schüpbach

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Localized Gurken (Grk) translation specifies the anterior-posterior and dorsal-ventral axes of the developing Drosophila oocyte; spindle-class females lay ventralized eggs resulting from inefficient grk translation. This phenotype is thought to result from inhibition of the Vasa RNA helicase. In a screen for modifiers of the eggshell phenotype in spn-B flies, we identified a mutation in the lnk gene. We show that lnk mutations restore Grk expression but do not suppress the persistence of double-strand breaks nor other spn-B phenotypes. This suppression does not affect Egfr directly, but rather overcomes the translational block of grk messages seen in spindle mutants. Lnk was recently identified as a component of the insulin/insulin-like growth factor signaling (IIS) and TOR pathway. Interestingly, direct inhibition of TOR with rapamycin in spn-B or vas mutant mothers can also suppress the ventralized eggshell phenotype. When dietary protein is inadequate, reduced IIS-TOR activity inhibits cap-dependent translation by promoting the activity of the translation inhibitor eIF4E-binding protein (4EBP). We hypothesize that reduced TOR activity promotes grk translation independent of the canonical Vasa- and cap-dependent mechanism. This model might explain how flies can maintain the translation of developmentally important transcripts during periods of nutrient limitation when bulk cap-dependent translation is repressed.

Original languageEnglish (US)
Pages (from-to)1407-1419
Number of pages13
JournalJournal of cell science
Volume125
Issue number6
DOIs
StatePublished - Mar 15 2012

All Science Journal Classification (ASJC) codes

  • Cell Biology

Keywords

  • Gurken
  • IRES
  • Lnk
  • TOR
  • Translation

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    Ferguson, S. B., Blundon, M. A., Klovstad, M. S., & Schüpbach, T. (2012). Modulation of gurken translation by insulin and TOR signaling in Drosophila. Journal of cell science, 125(6), 1407-1419. https://doi.org/10.1242/jcs.090381