JUL 26, 2020 5:06 AM PDT

How SARS-CoV-2 Works

WRITTEN BY: Carmen Leitch

Cell biologist Carolyn Machamer has studied viruses for the past 35 years, and has seen outbreaks caused by several pathogens including H1N1 influenza and the coronaviruses SARS and MERS. The importance of her research has never been more clear, as scientists around the world scramble to learn as much as they can about the pandemic coronavirus SARS-CoV-2, which has killed more than 643,000 people as of July 25, 2020. Machamer has emphasized the need for basic research that can tell us more about these pathogens.

“We need to know more about how these viruses work,” she said. “The knowledge can reveal hidden targets and an Achilles’ heel that could help us develop diagnostics and treatments to eradicate them quickly and efficiently.”

We do know some things about SARS-CoV-2; it's about one-hundredth the size of a cell, and it has a genome made of RNA. It's a coronavirus, a group of viruses that gained their name because of crown-like proteins on their surface, which can bind to receptors on human cells, as well as avian cells. Machamer uses an avian model to learn more about the SARS-CoV-2 virus.

When an infection occurs, the virus enters the body and after binding to a host cell receptor, it fuses to the host cell membrane and releases its contents into the cell. Once inside of the host cell, the first two-thirds of its genome is used to create structural proteins and copy the viral genome so that more viral particles can be generated. These will go on to infect more cells. Before these viruses are shipped out, however, they move to an organelle in the host cell called the Golgi apparatus. The Golgi normally helps sort and package proteins. New copies of the SARS-CoV-2 virus also seem to be assembled there. A part of its lipid envelope is made, and the virus gets packaged there into vesicles that move to the cell surface.

“It’s not the most efficient way to assemble viruses and get them out of a cell,” Machamer noted. “But there has to be a reason why this mechanism has persisted.”

Her work has recently shown that a bronchitis coronavirus can neutralize the pH of the Golgi apparatus, which may help the pathogens move out of the host cell.

Rubella is another virus that's known to assemble new viral particles at the Golgi. Other viruses including hepatitis C, West Nile, and Zika use a different organelle, the endoplasmic reticulum, to process their proteins.

Modified from a creative rendition of SARS-CoV-2 virus particles. Note: not to scale. / Credit: NIAID

There are many different coronaviruses other than SARS-CoV-2, which was not known to humans before late last year. Rhinoviruses, of which there are over 100 strains, and adenoviruses are known to cause around 80 percent of cases of the common cold, but the remaining 20 percent are caused by coronaviruses.

More effort will be needed to ensure that we're ready to face the threat posed by emerging pathogens. “We need to understand how these viruses work,” added Machamer, “and once we understand that, we’re in a better position to conquer them.”


Source: Johns Hopkins Medicine

About the Author
BS
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
JUL 24, 2022
Cell & Molecular Biology
Mitochondria & Metabolism Are Unique in Egg Cells
JUL 24, 2022
Mitochondria & Metabolism Are Unique in Egg Cells
Human egg cells, called oocytes, have to last a long time. They are created before birth, and they stay viable for many ...
JUL 25, 2022
Genetics & Genomics
Genetic Recombination Appears to be Common in the Human Genome
JUL 25, 2022
Genetic Recombination Appears to be Common in the Human Genome
When the genomes of parents come together to create the genome of a child, their DNA recombines; similar parts are rearr ...
JUL 31, 2022
Genetics & Genomics
A Brief History of Human Gene Editing
JUL 31, 2022
A Brief History of Human Gene Editing
DNA was characterized in 1953, and shortly after, the nature of the genetic code was revealed.
AUG 07, 2022
Cell & Molecular Biology
Vitamin K Revealed as Potent Cell Death Suppressor
AUG 07, 2022
Vitamin K Revealed as Potent Cell Death Suppressor
Researchers have known that vitamin K has antioxidant properties, but the mechanism behind that function remained obscur ...
AUG 15, 2022
Cell & Molecular Biology
Researchers Create the First Synthetic Mouse Embryo
AUG 15, 2022
Researchers Create the First Synthetic Mouse Embryo
Scientists have been able to create stem cells that can mimic the early stages of mouse development. The researchers use ...
SEP 06, 2022
Genetics & Genomics
Reduced A-to-I Editing in RNA Linked to Autoimmune Disorder Risk
SEP 06, 2022
Reduced A-to-I Editing in RNA Linked to Autoimmune Disorder Risk
The genome contains the sequences for protein-coding genes, but before those seuquences are translated into protein, the ...
Loading Comments...