Lightning Oral Talk 25th Annual Lorne Proteomics Symposium 2020

“RNA regulons” as potential drivers of Giardia duodenalis stage transition (#20)

Balu Balan 1 2 , Samantha Emery-Corbin 1 , Jarrod Sandow 1 , Andrew Webb 1 , Staffan Svard 3 , Aaron Jex 1 2
  1. Walter and Eliza Hall Institute, Parkville, VICTORIA, Australia
  2. Faculty of Veterinary and Agricultural Science, University of Melbourne , Melbourne, Victoria, Australia
  3. Cell and Molecular Biology, University of Uppsala, Uppsala, Stockholm, Sweden

Parasitic protists rapidly adapt to environment changes to survive and infect new hosts. These adaptations largely occur in absence of cell division and necessitate massive reconfigurations of transcriptional and expressional behaviors. These essential changes occur within minutes of invasion, such that they appear pre-programmed.

Pre-programming (‘cell-fating’) has been explored heavily in eukaryotic cells, including developmental biology and stem-cell differentiation. Post-transcriptional regulation (PTR), as mediated through translational repression, contributes to cell-fating by holding transcripts in stasis for later translation. RNA-binding proteins (RBPs) are essential in PTR, regulating multiple mRNAs through high order combinations known as “RNA regulons”.

Giardia duodenalisis a prevalent gastrointestinal parasite causing over 200 million cases of diarrhoeal disease. Understanding PTR mechanisms in Giardia will illuminate new systems to inhibit critical aspects of its infection biology, host interaction and resistance to frontline drugs. Further, Giardia provides a model to ‘close the gap’ between higher eukaryotes and deep-branching species to ascertain evolutionary origins of eukaryotic PTR mechanisms.

Our multi-omics study explored multiple dimensions of RBP repertoires in Giardia. We bioinformatically curated the currently undefined Giardia‘RBPome’ and mapped its transcriptomic and proteomics kinetics across stage transition. Towards this, we performed the first quantitative deep proteome map of the entire Giardia stage transition. We complimented this with interactome capture proteomic characterization of poly-A mRNAs bound proteins Giardiathrough stage transition in vitro, the first characterization of this kind in any protist. From these analyses we have identified a eukaryote conserved RBP which contain intrinsic disordered regions responsible for phase separating behavior in model eukaryotes. We plan to further explore the role of this RBP as regulator of translational repression in Giardia infection biology. Together, we provide the first multi-platform, multi-omic reference map of RBPs in Giardia towards understanding the role and evolution of “RNA regulons” in eukaryotes.