World’s first Zika clone developed | May lead to development of Quicker Countermeasures
Cloning the virus unlocks scientists’ ability to more quickly develop countermeasures and explore the evolution of the virus. For 60 years, the Zika virus remained obscure with few identified cases in people and mild disease symptoms. However, since 2007, the virus has sparked frequent epidemics associated with serious diseases such as microcephaly and Guillain-Barre syndrome.
In a development that could help unravel key questions about the spread of Zika virus and speed the hunt for drugs and vaccines, Texas researchers described the first genetically cloned version of the virus.
The Zika virus clone was developed by researchers at the University of Texas Medical Branch (UTMB) at Galveston, and the team reported its findings in Cell Host and Microbe.
“The new Zika clone, together with mosquito infection models and the UTMB-developed Zika mouse model, represent a major advance towards deciphering why the virus is tied to serious diseases,” said lead author Pei-Yong Shi, UTMB endowed professor. “The new clone is also a critical step in developing a vaccine and antiviral drug against Zika.”
The researchers first constructed the Zika virus clone. Five fragments spanning the complete viral genome
were individually cloned and assembled into the full-length clone of the Zika virus.The infectious cDNA clone allows researchers to make Zika virus from test tube and cells on petri dishes. The researchers then used the UTMB-developed Zika mouse model to demonstrate that the cloned virus infected the mice and gave them neurological disease.
The team fed Aedes aegypti mosquitoes, one of the types known to transmit Zika, with human blood infected with either the parental Zika virus or the “human-made” virus and found the number of infected mosquitoes was similar.
These findings confirm that the cloned virus is highly infectious for Aedes aegypti mosquitoes. In addition, the results demonstrated that Aedes aegypti might be a good mosquito vector for Zika virus transmission. Furthermore, the team engineered a luciferase reporter Zika virus. Luciferase is the chemical in fireflies that gives them their signature glow. The “glowing” reporter virus could be used for antiviral drug screening. In addition, the reporter signal could be used to track Zika virus infection in mosquitoes and small animal models.
“This is a good example of collaboration among different teams on UTMB campus. I joined UTMB about six months ago. Without collaborating with great colleagues, we would not be able to report such a comprehensive data package in the study,” said Shi. “In fact, many experiments were performed in Mariano Garcia-Blanco and Shelton Bradricks’ laboratories because my equipment had not yet fully arrived.” Other authors include UTMB’s Chao Shan, Xuping Xie, Antonio Muruato, Shannan Rossi, Christopher Roundy, Sasha Azar, Yujiao Yang, Robert Tesh, Nigel Bourne, Alan Barrett, Nikos Vasilakis and Scott Weaver.
