Researchers have recently identified a virus named FloV-SA2 that produces one of the essential proteins necessary for building ribosomes. Ribosomes are vital components in all cells that interpret genetic information to synthesize proteins, which are fundamental to life. This marks the first time a eukaryotic virus, which infects organisms like plants, animals, and fungi, has been found to produce such a protein.
Researchers at the University of Hawai’i at Manoa have uncovered that the virus FloV-SA2 encodes a vital protein for ribosome production. Ribosomes serve as crucial machinery in cells for translating genetic codes into proteins, which are the essential building blocks of life. Remarkably, this is the first instance of a eukaryotic virus (a virus that infects eukaryotes, such as plants, animals, fungi) being found to encode such a protein.
Viruses consist of genetic material encased in a protein shell. They replicate by infiltrating a host cell, commandeering its replication resources to produce more viruses. While simpler viruses rely almost entirely on the host cell for resources, larger and more intricate viruses have the capability to code for many proteins to facilitate their own replication.
“We were thrilled to discover that this virus produces a ribosomal protein known as eL40,” expressed Julie Thomy, the study’s lead author and a postdoctoral researcher at the Daniel K. Inouye Center for Microbial Oceanography: Research and Education (C-MORE) and the Department of Oceanography in the UH Manoa School of Ocean and Earth Science and Technology (SOEST). “It makes sense that a virus might gain an advantage by modifying such a crucial component of cellular machinery, but until now, there was no evidence for it in any eukaryotic virus.”
The discovery was part of a broader initiative by the Marine Viral Ecology Laboratories (MarVEL) in SOEST, aiming to isolate and characterize new ocean-dwelling viruses. Former Oceanography graduate student Christopher Schvarcz collected water samples from Station ALOHA, located 60 miles north of O’ahu, Hawai’i, and isolated numerous viruses. Among these was FloV-SA2, which targets a type of phytoplankton known as Florenciella.
“Chris was so productive at isolating viruses, he couldn’t analyze them all before he departed,” noted Grieg Steward, an Oceanography faculty member supervising the project. “In-depth analysis of this virus had to wait until Dr. Thomy joined the lab, but it was definitely worth the wait!”
Is the virus prioritizing its own protein production?
Past findings indicate that, similar to FloV-SA2, other so-called ‘giant’ viruses encode proteins that participate in various metabolic functions. Some of these roles, such as those related to fermentation or light sensing, are quite unexpected for a virus. These genes likely assist the virus in replication, but, as seen with the ribosomal protein, the precise mechanism is often unclear. The researchers are now working to understand how and when this protein is utilized by the virus.
“Our working hypothesis is that by integrating one of its own proteins into the ribosome, the virus modifies this critical machinery to favor the synthesis of viral proteins over the standard cellular proteins,” Thomy explained.
“Viruses play a vital role in ocean ecosystems by affecting biological productivity, altering community interactions, and driving evolutionary changes,” said Steward. “This find uncovers new insights into the complex interactions between ocean viruses and phytoplankton, which are the backbone of marine ecosystems. It also paves the way for a deeper understanding of basic viral biology.”
The researchers anticipate that FloV-SA2 will serve as a significant model for exploring new methods through which viruses influence cellular metabolism and redirect the host’s resources and energy.
