Developmental Biology - Coronavirus|
New Coronavirus Testing Kits Under Development
Canadian researchers have developed a coronavirus test that can detect a single positive RNA strand in the virus...
Simon Fraser University (SFU) researchers will use their pioneering imaging technology - called Mango, for its bright color - to develop coronavirus testing kits. They're among a small set of Canadian researchers who responded to the rapid funding opportunity recently announced by the Canadian Institutes of Health Research (CIHR) to help address COVID-19.
SFU researchers Lena Dolgosheina, a post-doctoral fellow and Peter Unrau, a professor of molecular biology and biochemistry, developed Mango to sensitively detect RNA molecules, helping to improve viral screening for viruses such as the coronavirus while enabling basic discoveries into the functioning of cells.
The latest research involves using Mango to detect individual molecules of RNA within a living cell.
"We are made of molecules so when something goes wrong within a cell it happens at the molecular level, says Peter Unrau. "We are using the Mango system as a catalyst, to allow us to not only extend fundamental research questions but also to detect pathogens like the coronavirus, faster and more efficiently."
The Mango system consists of an RNA Mango aptamer that binds tightly and specifically to a fluorescent dye. The aptamer acts like a magnet - targeting and binding to dye molecules. The dye then becomes excitable when bound and begins to glow brightly. RNA molecules modified to contain the aptamer 'magnet' now stand out from other parts of the cell and are now much easier for researchers to see and study under a microscope.
"Cell regulation takes place at the level of RNA. For a long time, the focus has been on protein but it is RNA and not protein that regulates the vast majority of processes within a cell."
Peter J. Unrau PhD, Department of Molecular Biology and Biochemistry, Simon Fraser University, British Columbia, Canada.
RNA Mango dyes are currently available from Applied Biological Materials (ABM) in Richmond, British Columbia. The coronavirus research made possible by CIHR funding will allow the team to develop an isothermal testing methodology. Mango NABSA (Nucleic Acid Sequence-based Amplification) kits can be used to test for coronavirus as it is a positive strand RNA virus.
The team's research is published in Nature Communications.
RNA molecules play vital roles in many cellular processes. Visualising their dynamics in live cells at single-molecule resolution is essential to elucidate their role in RNA metabolism. RNA aptamers, such as Spinach and Mango, have recently emerged as a powerful background-free technology for live-cell RNA imaging due to their fluorogenic properties upon ligand binding. Here, we report a novel array of Mango II aptamers for RNA imaging in live and fixed cells with high contrast and single-molecule sensitivity. Direct comparison of Mango II and MS2-tdMCP-mCherry dual-labelled mRNAs show marked improvements in signal to noise ratio using the fluorogenic Mango aptamers. Using both coding (?-actin mRNA) and long non-coding (NEAT1) RNAs, we show that the Mango array does not affect cellular localisation. Additionally, we can track single mRNAs for extended time periods, likely due to bleached fluorophore replacement. This property makes the arrays readily compatible with structured illumination super-resolution microscopy.
Adam D. Cawte, Peter J. Unrau and David S. Rueda.
The authors would like to thank Dirk Dormann and Chad Whilding from the MRC-London Institute of Medical Sciences microscopy facility, Prof. Jorge Ferrer and Dr. Anthony Beucher for providing the pLenti plasmid and members of the Unrau lab for synthesising TO1-Biotin. The Single Molecule Imaging Group is funded by a core grant of the MRC-London Institute of Medical Sciences (UKRI MC-A658-5TY10), a Wellcome Trust Collaborative Grant (206292/Z/17/Z) and a Leverhulme Trust Grant (RPG-2016-214). PJU acknowledges NSERC Canada Discovery grant.
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The Canadian Institutes of Health Research will use pioneering imaging technology from Simon Fraser University - called Mango, for its bright color - to develop coronavirus testing kits.
CREDIT Simon Fraser University, Canada.