Unusual DNA Form May Help Virus Withstand Extreme Conditions

A, B and Z DNA.
DNA comes in three forms: A, B and Z. Credit: A-DNA, B-DNA and Z-DNA by Zephyris (Richard Wheeler) under CC BY-SA 3.0.

DNA researcher Rosalind Franklin Exit icon first described an unusual form of DNA called the A-form in the early 1950s (Franklin, who died in 1958, would have turned 95 next month). New research on a heat- and acid-loving virus has revealed surprising information about this DNA form, which is one of three known forms of DNA: A, B and Z.

“Many people have felt that this A-form of DNA is only found in the laboratory under very non-biological conditions, when DNA is dehydrated or dry,” says Edward Egelman Exit icon in a University of Virginia news release Exit icon about the recent study. But considered with earlier studies on bacteria by other researchers, the new findings suggest that the A-form “appears to be a general mechanism in biology for protecting DNA.” Continue reading “Unusual DNA Form May Help Virus Withstand Extreme Conditions”

Meet Nels Elde and His Team’s Amazing, Expandable Viruses

Nels Elde, Ph.D.
Credit: Kristan Jacobsen
Nels Elde, Ph.D.
Fields: Evolutionary genetics, virology, microbiology, cell biology
Works at: University of Utah, Salt Lake City
When not in the lab, he’s: Gardening, supervising pets, procuring firewood
Hobbies: Canoeing, skiing, participating in facial hair competitions

“I really look at my job as an adventure,” says Nels Elde. “The ability to follow your nose through different fields is what motivates me.”

Elde has used that approach to weave evolutionary genetics, bacteriology, virology, genomics and cell biology into his work. While a graduate student at the University of Chicago and postdoctoral researcher at the Fred Hutchinson Cancer Research Center in Seattle, he became interested in how interactions between pathogens (like viruses and bacteria) and their hosts (like humans) drive the evolution of both parties. He now works in Salt Lake City, where, as an avid outdoorsman, he draws inspiration from the wild landscape.

Outside the lab, Elde keeps diverse interests and colorful company. His best friend wrote a song about his choice of career as a cell biologist. (You can hear this song at the end of the 5-minute video Exit icon in which Elde explains his work.) Continue reading “Meet Nels Elde and His Team’s Amazing, Expandable Viruses”

Dormant Viruses Reactivate, Signaling Effect of Lingering Sepsis

Doctors with a patient
A new study finds that people with lingering sepsis may have suppressed immune systems. Credit: Stock image.

Each year, more than 200,000 people in the United States die from sepsis, a condition caused by an overwhelming immune response that can quickly lead to organ failure. While many people with sepsis survive this immediate threat, they may die days or even months later from secondary infections.

A research team that included Richard Hotchkiss, Jonathan Green and Gregory Storch of Washington University School of Medicine in St. Louis suspected that when sepsis lasts for more than a few days, it compromises the immune system. To test this hypothesis, the scientists compared viral activity in sepsis patients, other critically ill patients and healthy individuals. They looked for viruses like Epstein-Barr and herpes-simplex that are often dormant and innocuous in healthy people but can reactivate and cause problems in those with suppressed immune systems.

Of the three study groups, sepsis patients had much higher levels of these viruses, suggesting that their immune responses may be hindered. Immune suppression could make it difficult to defend against the reactivated viruses as well as new infections like pneumonia. The team now plans to test whether immune-boosting drugs can prevent deaths in people with lingering sepsis.

Learn More:
Washington University in St. Louis News Release Exit icon
NIGMS Sepsis Fact Sheet

Learning How Mosquito-Borne Viruses Use Knot-like RNA to Cause Disease

A knot-like structure in a section of RNA from a flavivirus
A knot-like structure in RNA enables flaviviruses to cause diseases like yellow fever, West Nile virus and dengue fever, which threaten roughly half the world’s population. Credit: Jeffrey Kieft.

Roughly half the world’s population is now at risk for mosquito-borne diseases other than malaria, such as yellow fever, West Nile virus and dengue fever. These three diseases are caused by flaviviruses, a type of virus that carries its genetic material as a single strand of RNA.

Flaviviruses have found a way not only to thwart our bodies’ normal defenses, but also to harness a human enzyme—paradoxically, one normally used to destroy RNA—to enhance their disease-causing abilities. A team of scientists led by Jeffrey Kieft at the University of Colorado at Denver found that flaviviruses accomplish both feats by bending and twisting a small part of their RNA into a knot-like structure.

The scientists set out to learn more about this unusual ability. First, they determined the detailed, three-dimensional architecture of the convoluted flaviviral RNA. Then, they examined several different variations of the RNA. In doing so, they pinpointed parts that are critical for forming the knot-like shape. If researchers can find a way to prevent the RNA from completing its potentially dangerous twist, they’ll be a step closer to developing a treatment for flaviviral diseases, which affect more than 100 million people worldwide.

This work also was supported by the National Institute of Allergy and Infectious Diseases and the National Cancer Institute.

Learn more:
University of Colorado News Release exit icon
Kieft Lab exit icon