Clouse K Nicole, Ferguson Scott B, Schüpbach Trudi
Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Dev Biol. 2008 Jan 15;313(2):713-24. doi: 10.1016/j.ydbio.2007.11.008. Epub 2007 Nov 19.
During Drosophila melanogaster oogenesis, the proper localization of gurken (grk) mRNA and protein is required for the establishment of the dorsal-ventral axis of the egg and future embryo. Squid (Sqd) is an RNA-binding protein that is required for the correct localization and translational regulation of the grk message. We show that Cup and polyA-binding protein (PABP) interact physically with Sqd and with each other in ovaries. We show that cup mutants lay dorsalized eggs, enhance dorsalization of weak sqd alleles, and display defects in grk mRNA localization and Grk protein accumulation. In contrast, pAbp mutants lay ventralized eggs and enhance grk haploinsufficiency. PABP also interacts genetically and biochemically with Encore. These data predict a model in which Cup and Sqd mediate translational repression of unlocalized grk mRNA, and PABP and Enc facilitate translational activation of the message once it is fully localized to the dorsal-anterior region of the oocyte. These data also provide the first evidence of a link between the complex of commonly used trans-acting factors and Enc, a factor that is required for grk translation.
在黑腹果蝇卵子发生过程中，gurken（grk）mRNA和蛋白质的正确定位对于卵子和未来胚胎背腹轴的建立是必需的。Squid（Sqd）是一种RNA结合蛋白，对于grk信息的正确定位和翻译调控是必需的。我们发现Cup和多聚腺苷酸结合蛋白（PABP）在卵巢中与Sqd相互作用，并且彼此之间也相互作用。我们发现cup突变体产下背化的卵子，增强了弱sqd等位基因的背化作用，并在grk mRNA定位和Grk蛋白积累方面表现出缺陷。相反，pAbp突变体产下腹化的卵子并增强grk单倍剂量不足。PABP还在遗传和生化水平上与Encore相互作用。这些数据预测了一个模型，其中Cup和Sqd介导未定位的grk mRNA的翻译抑制，而PABP和Enc在grk信息完全定位于卵母细胞的背前部区域后促进其翻译激活。这些数据还首次证明了常用反式作用因子复合物与Enc（grk翻译所需的一个因子）之间存在联系。
