Poster Presentation 25th Annual Lorne Proteomics Symposium 2020

Coordinated post-transcriptional and post-translational regulation through stage transition of Giardia duodenalis (#144)

Qiao Su 1 2 , Samantha Emery-Corbin 1 , Balu Balan 1 3 , Staffan G Svärd 4 , Ivo Mueller 1 5 , Aaron Jex 1 3
  1. Walter and Eliza Hall Institute, MELBOURNE, VIC, Australia
  2. Faculty of Medicine, Dentistry and Health Science, University of Melbourne, Melbourne, VIC, Australia
  3. Faculty of Veterinary and Agricultural Science, University of Melbourne, MELBOURNE, VIC, Australia
  4. Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
  5. Malaria Parasites and Hosts Unit, Pasteur Institute, Paris, France

Giardia duodenalis is a gastrointestinal parasite responsible for 200-300 million cases of diarrheal disease worldwide, with direct transmission via fecal-oral route. Transmission depends stage transition from binucleate, flagellated trophozoite to tetranucleate cysts, a process considered one of simplest developmental transition within eukaryotes. Studies show parasites induced in vitro are irreversibly committed to the encystation process by 3-6 hours, undergoing dramatic changes to gene transcription and translation toward shifting energy metabolism, protein production and requisite epigenetic remodeling. Independent transcriptomic and proteomic studies have demonstrated that encystation is defined by temporally regulated cascades of required encystation genes and pathways, and we hypothesize these are coordinated through post-transcriptional and post-translational regulation.

In this study, we have generated same pellet RNA and protein for deep-sequencing from the predominant human-infective Giardia duodenalis sub-species (isolate GS). Our six-point time-series across encystation includes steady-growth, pre-encystation priming, three early to mid-encystation timepoints and the mature cyst. Quantitation will allow us to dynamically follow the transcript-protein correlation throughout developmental transitions to identify post-transcriptional or post-translational regulatory events. Towards this, we will specifically curate RNA-binding proteins of this human-infective sub-species to monitor their kinetics, which can be followed by interactome capture at significant timepoints. Further, we are quantitating H3 and H4 acetylysine and methyllysine marks through priming and early-mid encystation via immunoblotting, covering the critical ‘point-of-no-return’ during which the parasite commits to stage transition.

Combining quantitative transcriptomics and proteomics for the first time, this study will provide the resolution to understand the regulation of stage transition in Giardia, which will provide novel insights into processes critical to interrupt its transmission towards new interventions and drug development.