Do trypanosomes control mRNA export?

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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.