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 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
DEC 04, 2018
Genetics & Genomics
DEC 04, 2018
The All-you-can-eat Gene?
Many people dream of being able to eat the foods they want without having to worry about weight gain. New research shows it may one day be possible....
DEC 10, 2018
Neuroscience
DEC 10, 2018
Scientist found genes to promote spinal cord regeneration
lay out a path that neurons of the spinal cord might be able to follow - potentially leading to improved recovery for people paralyzed by spinal cord injuries....
DEC 15, 2018
Cell & Molecular Biology
DEC 15, 2018
HIV Vaccine Successful in Non-human Primates
Researchers have been trying to create a vaccine for HIV, the virus that causes AIDS, for decades....
DEC 18, 2018
Videos
DEC 18, 2018
A Look at the Tumor Microenvironment
The video above features the latest Koch Institute Image Award winner....
JAN 07, 2019
Health & Medicine
JAN 07, 2019
Associations Between Secondhand Smoke Exposure and the Development of All Cancers
  Researchers in the 1930s, 1940s, and 1950s began to amass evidence of the adverse effects of secondhand smoke; In 1957, Surgeon General Leroy Burney...
JAN 07, 2019
Microbiology
JAN 07, 2019
New Insight Into HPV Opens up Potential Treatment Avenues
Human papillomavirus (HPV) causes nearly every case of cervical cancer....
Loading Comments...