Researchers at the University of Hawaii at Mānoa discovered a virus called FloV-SA2 that encodes an important protein required for ribosome production. Ribosomes are key cellular structures that convert genetic information into proteins - the basic building blocks of life. This is the first time a eukaryotic virus (viruses that infect organisms such as plants, animals or fungi) has been found to encode this protein.
Viruses are essentially packets of genetic material wrapped in a protein coat. They reproduce more viruses by invading host cells and exploiting the host cell's replication machinery. While simpler viruses rely almost entirely on host cells to complete this process, larger and more complex viruses often produce a variety of proteins to assist in their replication.
"We were pleased to find that this virus encodes a ribosomal protein called eL40," said Julie Thomy, first author of the study and a postdoctoral researcher in the Department of Oceanography at the Daniel K. Inouye Center for Microbial Oceanography Research and Education (C-MORE) and the University of Manoa's School of Marine Earth Science and Technology (SOEST). "It makes sense that viruses could benefit from altering this key cellular mechanism, but there is no evidence of this in any eukaryotic virus."
The discovery of this virus is part of a larger effort by members of SOEST's Marine Virus Ecology Laboratory (MarVEL) to isolate and characterize new viruses living in the ocean. Former oceanography graduate student Christopher Schvarcz collected water samples from the ALOHA station 60 miles north of Oahu, Hawaii, and subsequently isolated dozens of viruses. These include FloV-SA2, which infects a phytoplankton species called Florenciella.
"Chris was so efficient at isolating viruses that he couldn't analyze them all before he left," said Grieg Steward, the oceanography instructor who led the project. "Detailed analysis of this virus will have to wait until Dr. Twomey joins the lab, but it will be worth the wait!"
Previous findings have shown that, like the FloV-SA2 virus, other so-called "giant" viruses encode proteins involved in various metabolic processes. Some genes, such as those involved in fermentation or light sensing, have seemingly surprising functions found in viruses. These genes must contribute to the replication of the virus, but like the ribosomal proteins, it is not always clear how. Researchers are now focused on figuring out the details of how and when the virus uses this protein.
"Our working hypothesis is that by inserting one of its own proteins into the ribosome, the virus changes this key mechanism in a way that favors the production of viral proteins instead of the usual cellular proteins," Twomey said.
"Viruses are integral to the functioning of marine ecosystems, affecting biological productivity, altering community interactions and driving evolutionary change," Steward said. "This discovery reveals new details about the complex ways in which viruses in the ocean interact with phytoplankton, the foundation of marine ecosystems, while also opening up new ways for us to understand the fundamentals of viral biology."
The scientists anticipate that FloV-SA2 will become a valuable model system for studying novel mechanisms by which viruses manipulate cellular metabolism and reallocate host resources and energy.
Compiled from /scitechdaily