Opposing roles for Egalitarian and Staufen in transport, anchoring and localization of oskar mRNA in the Drosophila oocyte.
Opposing roles for Egalitarian and Staufen in transport, anchoring and localization of oskar mRNA in the Drosophila oocyte.
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DOI：
10.1371/journal.pgen.1009500
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发表时间：
2021-04
期刊：
影响因子：
4.5
通讯作者：
Macdonald PM
中科院分区：
文献类型：
--
作者：
Mohr S;Kenny A;Lam STY;Morgan MB;Smibert CA;Lipshitz HD;Macdonald PM
Oskar mRNA的定位包括两个不同的阶段：从哺育细胞到卵母细胞的运输，这个过程通常伴随着卵母细胞中的皮质锚定，随后是卵母细胞内的后部定位。在Oskar 3‘UTR中引导传输的信号单独很弱，这是先前假设的一个特征，以促进不同本地化机器之间的交换。我们表明，包含Oskar运输和锚定信号(TAS)的SL2a茎环结构的改变消除了一种抑制效应，从而在体外与平等性RNA运输因子的结合增加，就像在体内从哺育细胞到卵母细胞的运输一样。卵母细胞内的皮质锚定也得到加强，干扰了后部定位。我们还发现，Staufen识别结构(SRSS)的突变，预测了Staufen的结合位点，就像Staufen突变体一样，破坏了Oskar mRNA的后继定位。SL2a中的两个SRSS，一个与平等结合位点重叠，被推测介导了Staufen依赖的对TAS锚定活性的抑制，从而促进了后定位。Oskar 3‘UTR中的其他三个SRS也需要用于后方定位，其中两个位于远离任何已知传输信号的位置。因此，Staufen在Oskar mRNA的定位中起着多重作用。在细胞内，许多成分必须在特定的亚细胞位置得到浓缩。实现蛋白质非随机分布的一种机制是对其同源mRNA进行定位。当一个信使核糖核酸的定位涉及不止一个步骤时，必须将信使核糖核酸从指导第一步的机器上释放出来，以使下一步的机器能够执行其功能。对于果蝇Oskar信使核糖核酸，第一步是将信使核糖核酸从其合成部位运输到卵母细胞，下一步是将信使核糖核酸定位到卵母细胞的后极。先前的研究表明，Oskar mRNA中调节运输的多个信号必然单独较弱，以促进后部定位机制的行动。在这里，我们描述了一个突变版本的Oskar mRNA，其行为表明与运输机械的过度坚韧的联系，导致了后遗症定位的失败。生化研究表明，突变信号增强了与介导转运的平等RNA结合蛋白的结合。遗传学研究表明，Staufen RNA结合蛋白具有相反的作用，促进从运输机制中解离，从而实现后定位。
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. Within cells, many components must be enriched at specific subcellular locations. One mechanism to achieve the nonrandom distribution of a protein is localization of its cognate mRNA. When localization of an mRNA involves more than one step, the mRNA must be released from the machinery directing the first step to allow the machinery for the next step to perform its function. For the Drosophila oskar mRNA the first step is transport of the mRNA from its site of synthesis to the oocyte, where the next step is localization of the mRNA to the posterior pole of the oocyte. Prior studies suggested that the multiple signals in the oskar mRNA that mediate transport were individually weak by necessity, to facilitate action by the posterior localization machinery. Here, we describe a mutant version of the oskar mRNA whose behavior suggests an overly tenacious association with the transport machinery, leading to failure in posterior localization. Biochemical studies show that the mutant signal has enhanced binding to the Egalitarian RNA binding protein, which mediates transport. Genetic studies show that the Staufen RNA binding protein has an opposing role, facilitating dissociation from the transport machinery to enable posterior localization.
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影响因子：
14.9
作者：
Larkin A;Marygold SJ;Antonazzo G;Attrill H;Dos Santos G;Garapati PV;Goodman JL;Gramates LS;Millburn G;Strelets VB;Tabone CJ;Thurmond J;FlyBase Consortium
通讯作者：
FlyBase Consortium
DOI：
10.1261/rna.048298.114
发表时间：
2015-06
期刊：
RNA (New York, N.Y.)
影响因子：
--
作者：
Kanke M;Jambor H;Reich J;Marches B;Gstir R;Ryu YH;Ephrussi A;Macdonald PM
通讯作者：
Macdonald PM
影响因子：
4.5
作者：
Kim G;Pai CI;Sato K;Person MD;Nakamura A;Macdonald PM
通讯作者：
Macdonald PM
影响因子：
4.6
作者：
Jenny, Andreas;Hachet, Olivier;Ephrussi, Anne
通讯作者：
Ephrussi, Anne
影响因子：
14.9
作者：
Laver, John D.;Li, Xiao;Lipshitz, Howard D.
通讯作者：
Lipshitz, Howard D.