Opposing roles for Egalitarian and Staufen in transport, anchoring and localization of oskar mRNA in the Drosophila oocyte

Autoři: Sabine Mohr aff001;  Andrew Kenny aff001;  Simon T. Y. Lam aff002;  Miles B. Morgan aff001;  Craig A. Smibert aff002;  Howard D. Lipshitz aff002;  Paul M. Macdonald aff001
Působiště autorů: Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, United States of America aff001;  Department of Molecular Genetics, University of Toronto, Toronto, Canada aff002;  Department of Biochemistry, University of Toronto, Toronto, Canada aff003
Vyšlo v časopise: Opposing roles for Egalitarian and Staufen in transport, anchoring and localization of oskar mRNA in the Drosophila oocyte. PLoS Genet 17(4): e1009500. doi:10.1371/journal.pgen.1009500
Kategorie: Research Article
doi: 10.1371/journal.pgen.1009500


Localization of oskar mRNA includes two distinct phases: transport from nurse cells to the oocyte, a process typically accompanied by cortical anchoring in the oocyte, followed by posterior localization within the oocyte. Signals within the oskar 3’ UTR directing transport are individually weak, a feature previously hypothesized to facilitate exchange between the different localization machineries. We show that alteration of the SL2a stem-loop structure containing the oskar transport and anchoring signal (TAS) removes an inhibitory effect such that in vitro binding by the RNA transport factor, Egalitarian, is elevated as is in vivo transport from the nurse cells into the oocyte. Cortical anchoring within the oocyte is also enhanced, interfering with posterior localization. We also show that mutation of Staufen recognized structures (SRSs), predicted binding sites for Staufen, disrupts posterior localization of oskar mRNA just as in staufen mutants. Two SRSs in SL2a, one overlapping the Egalitarian binding site, are inferred to mediate Staufen-dependent inhibition of TAS anchoring activity, thereby promoting posterior localization. The other three SRSs in the oskar 3’ UTR are also required for posterior localization, including two located distant from any known transport signal. Staufen, thus, plays multiple roles in localization of oskar mRNA.

Klíčová slova:

3' UTR – Eggs – Embryos – Luciferase – Oocytes – Oogenesis – RNA transport – Transport inhibition assay


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