title: Klar ensures thermal robustness of oskar localization by restraining RNP motility.
abstract: Communication usually applies feedback loop-based filters and amplifiers to ensure undistorted delivery of messages. Such an amplifier acts during Drosophila melanogaster midoogenesis, when oskar messenger ribonucleic acid (mRNA) anchoring depends on its own locally translated protein product. We find that the motor regulator Klar β mediates a gain-control process that prevents saturation-based distortions in this positive feedback loop. We demonstrate that, like oskar mRNA, Klar β localizes to the posterior pole of oocytes in a kinesin-1-dependent manner. By live imaging and semiquantitative fluorescent in situ hybridization, we show that Klar β restrains oskar ribonucleoprotein motility and decreases the posterior-ward translocation of oskar mRNA, thereby adapting the rate of oskar delivery to the output of the anchoring machinery. This negative regulatory effect of Klar is particularly important for overriding temperature-induced changes in motility. We conclude that by preventing defects in oskar anchoring, this mechanism contributes to the developmental robustness of a poikilothermic organism living in a variable temperature environment.
authors: European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
authors: Imre
authors: I
authors: Gaspar
authors: Department of Biology, University of Rochester, Rochester, NY 14627.
authors: Yanxun V
authors: YV
authors: Yu
authors: Department of Biology, Brandeis University, Waltham, MA 02454.
authors: Sean L
authors: SL
authors: Cotton
authors: Department of Biology, Brandeis University, Waltham, MA 02454.
authors: Dae-Hwan
authors: DH
authors: Kim
authors: European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
authors: Anne
authors: A
authors: Ephrussi
authors: Department of Biology, University of Rochester, Rochester, NY 14627 Department of Biology, Brandeis University, Waltham, MA 02454 michael.welte@rochester.edu.
authors: Michael A
authors: MA
authors: Welte
mesh_terms: D000818:Animals; D016764:Cell Polarity; D029721:Drosophila Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology / Q000378:metabolism*; D025461:Feedback, Physiological; D017404:In Situ Hybridization, Fluorescence; D016547:Kinesins / Q000378:metabolism / Q000502:physiology; D026901:Membrane Transport Proteins / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D009865:Oocytes / Q000378:metabolism; D021381:Protein Transport; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D013696:Temperature
chemical_list: D029721:Drosophila Proteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D012261:Ribonucleoproteins; C401521:klar protein, Drosophila; C091675:osk protein, Drosophila; D016547:Kinesins