Posttransscriptonal regulation of the nanos mRNA in Drosophila melanogaster

nanos mRNA编码果蝇胚胎后端发育的关键决定因素。纳米RNA受到严格的转录后控制：非定位的纳米RNA死基化和翻译抑制。死基化和抑制都是由3' UTR中Smaug蛋白（Smaug response elements, SREs）的结合位点控制的。位于后极的纳米RNA被奥斯卡激活。我们已经开发了一个无细胞系统，再现sre依赖的翻译抑制和deadenylation以及Oskar激活。我们发现，以sre依赖的方式组装的抑制子复合物在最早可检测的阶段阻止了翻译的启动。阻遏物复合体的组装是缓慢的，需要ATP，并且该复合体在动力学上异常稳定。阻遏物复合体包含Smaug和CCR4-NOT复合体，一种已知的deadenylase。它还含有几种已知参与其他翻译抑制的蛋白质，特别是rna依赖性atp酶Me31B。我们现在想要分析sre依赖性抑制复合物的组成，它导致翻译抑制和死基化的机制以及该复合物的各个组分的作用。

The nanos mRNA encodes a key determinant for development of the posterior end of the Drosophila embryo. Nanos is under strict posttranscriptional control: Non-localized nanos RNA is deadenylated and translationally repressed. Both deadenylation and repression are governed by binding sites for the protein Smaug (Smaug response elements, SREs) in the 3' UTR. Nanos RNA localized at the posterior pole is activated by Oskar. We have developed a cell-free system that reproduces SRE-dependent translational repression and deadenylation as well as activation by Oskar. We have found that a repressor complex assembled in an SRE-dependent manner prevents the initiation of translation at the earliest detectable stage. Assembly of the repressor complex is slow and requires ATP, and the complex is kinetically unusually stable. The repressor complex contains Smaug and the CCR4-NOT complex, a known deadenylase. It also contains several proteins known to be involved in other cases of translational repression, in particular the RNA-dependent ATPase Me31B. We now want to analyze the composition of the SRE-dependent repressor complex, the mechanism by which it causes translational repression and deadenylation and the roles of individual components of the complex.