Do trypanosomes control mRNA export?

在真核生物中，mRNA在细胞核中转录，但在细胞质中作为蛋白质产生的模板。因此，每一种mRNA都需要通过包围细胞核的双层膜屏障：核被膜。据信，真核生物控制mRNA输出，以防止不成熟或有缺陷的mRNA到达细胞质，从而防止产生潜在的毒性蛋白质。与这一观点相一致，在酵母和人类中鉴定了精细的mRNA输出控制系统。锥虫很早就离开了真核生物的主流，并且缺乏这些出口控制系统的许多组件的同源物。此外，我们最近发现，锥虫可以开始核输出，即使转录和mRNA加工没有完成。因此，锥虫要么有一个简单得多的mRNA输出控制系统，或者可能没有。我们将筛选在实验操作RNA特征或蛋白质后发生的mRNA输出变化，这些RNA特征或蛋白质在输出控制中具有疑似功能。我们将使用单分子原位杂交作为主要方法，并通过qPCR和细胞核和细胞质RNA的RNA测序来确认重要结果。我们的实验将回答这个问题，mRNA输出控制是否是所有真核生物的特征，或者它是否只在真核生物进化的后期阶段的一个亚群中进化。如果锥虫有一个更简单的mRNA输出系统，我们将确定其主要特征，这种方式有助于更好地了解真核生物中mRNA输出控制的进化。

In eukaryotes, mRNAs are transcribed in the nucleus, but serve as templates for protein production in the cytoplasm. Thus, every mRNA needs to pass the double-membraned barrier that surrounds the nucleus: the nuclear envelope. It is believed that eukaryotes control mRNA export, to prevent immature or faulty mRNAs from reaching the cytoplasm to prevent the production of potentially toxic proteins. Consistent with this view, elaborate mRNA export control systems were identified in yeast and human. Trypanosomes left the eukaryotic mainstream early and lack homologues to many of the components of these export control systems. Moreover, we recently found that trypanosomes can start nuclear export even though transcription and mRNA processing are not finished. Thus, trypanosomes either have a much simpler mRNA export control system, or perhaps none.We plan to study nuclear export control in trypanosomes in a systematic way. We will screen for changes in mRNA export that occur after experimental manipulation of RNA features or proteins with a suspected function in export control. We will use single molecule in situ hybridisation as the major method and confirm important results by qPCR and RNA sequencing of nuclear and cytoplasmic RNAs. Our experiments will answer the question, whether mRNA export control is a feature of all eukaryotes, or whether it has evolved only in a subgroup at a later stage in eukaryotic evolution. In case trypanosomes have a simpler mRNA export system, we will have identified its main features and this way contribute to a better understanding of the evolution of mRNA export control in eukaryotes.