JUN 22, 2016 11:30 AM PDT

Seeing How a Cold Penetrates Cells

WRITTEN BY: Carmen Leitch
After a cold virus (rhinovirus) gets into our bodies it must get access to our cells in order to release its RNA and multiply. However, the mechanism by which the RNA is transferred is not well-understood or easy to study. Researchers at The Vienna University of Technology or TU Wien have created a new method to investigate this process that takes advantage of two established procedures, capillary electrophoresis on chips and molecular beacons. Their study is published in the journal of Analytical and Bioanalytical Chemistry.
A representation of the molecular surface of one variant of human rhinovirus from Wikipedia
The structure of a rhinovirus is relatively simple, consisting of a shell or capsid made of four different proteins with 60 of each that are arranged in an icosahedron. The viral RNA is contained within it.

“Certain external conditions can also cause the virus to release its RNA to the outside,” says Victor Weiss, first author of this study. “In our cells this is triggered by a lower pH value; you can also achieve the same effect by increasing the temperature to 57 °C for ten minutes”. In this particular case, the proteins first rearrange themselves; the capsid of the virus then forms holes from which the RNA is released.
Coronaviruses are a group of viruses known for causing the common cold.
This type of in-depth understanding is critical for a number of medical reasons including for drug development that would prevent the RNA release. The new technique has made it possible to view the dynamics of this process directly.

Molecular beacons were used for this work. They are specialized molecules of RNA or DNA that have a fluorophore at one end and a quencher at the other. The fluorophore will flash if light of a particular wavelength - a laser - is shined on it while the quencher prevents the flashing. Victor Weiss explains, “To begin with, the molecule is folded up; the fluorophore and quencher are positioned very close to one another, then the fluorescence is very low.”

These beacons can be made to hybridize to a very specific sequence of RNA. When that happens, the molecule unfolds and the fluorophore and quencher are suddenly far apart from one another. When a suitable laser light is shined on the molecule, it lights up. Thus, molecular beacons can verify an RNA sequence.
In this schematic of the strategy provided by the study authors, RNA released from a cold virus is detected by chip electrophoresis after an increase in fluorescence since the beacon has attached itself to that RNA
The second proven technique that was used in the study is capillary electrophoresis, separation of components of a sample by moving it through an electric field. The final procedure works like this: a small sample of liquid is put in a channel where an electric field is applied. Various nanoparticles then migrate at different speeds based on their makeup. After a separation distance of about one and a half centimeters, a laser beam strikes the particle. The unfolded molecular beacon that is attached to the viral RNA lights up, and the fluorescence is measured.

"The different components of the sample reach the laser at different times. This is the only way to be sure that you are actually measuring exactly what you want to measure," explains Günter Allmaier, director of TU Wien and senior author of the study. "We can now demonstrate, for example, from which end of the RNA the virus first emerges, and how this process actually works."

“To us it's about developing the method; as a test object, the cold virus is virtually ideal," continues Allmaier. "However, we do of course hope that this method is established in medical research. We have now shown what great potential it has and this is also apparent in the partnership with Agilent Technologies."

Sources: AAAS via TU Wien News, Analytical and Bioanalytical Chemistry
 
About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 08, 2020
Neuroscience
Thyroid Inflammation Linked to Anxiety Disorder
SEP 08, 2020
Thyroid Inflammation Linked to Anxiety Disorder
Findings from a new study suggest that people with autoimmune inflammation in their thyroid may be more likely to develo ...
SEP 11, 2020
Drug Discovery & Development
Single Injection Sends Type 2 Diabetes into Remission
SEP 11, 2020
Single Injection Sends Type 2 Diabetes into Remission
Type 2 diabetes affects around 10% of people in the US. Although there is no cure for it, there are some well-known meth ...
OCT 11, 2020
Cell & Molecular Biology
Newly-Found Molecules May Treat Neurodegeneration
OCT 11, 2020
Newly-Found Molecules May Treat Neurodegeneration
The NMDA receptor is known to play a crucial role in memory, and synaptic plasticity - where neurons change, altering ne ...
OCT 18, 2020
Genetics & Genomics
'Silent' Mutations Might Have Given SARS-CoV-2 an Edge
OCT 18, 2020
'Silent' Mutations Might Have Given SARS-CoV-2 an Edge
The pandemic virus SARS-CoV-2 is thought to have originated in bats, like many viruses. To make the leap and infect anot ...
OCT 19, 2020
Plants & Animals
Genetically Engineered Foods Could Alleviate Nutritional Deficiencies
OCT 19, 2020
Genetically Engineered Foods Could Alleviate Nutritional Deficiencies
There are over two billion people around the world that don't get the recommended levels of minerals and vitamins in ...
OCT 19, 2020
Cell & Molecular Biology
Mapping the Human Proteome
OCT 19, 2020
Mapping the Human Proteome
To learn more about biology and medicine, researchers have used advances in molecular techniques and computational biolo ...
Loading Comments...