New Insights Detail Immature Zika Virus Structure

Highlights

• Zika virus is a mosquito-borne disease which causes abnormally small head (microcephaly) and brain inflammation in the newborns
• Details of the //immature zika virus structure was recently studied by a research team from Purdue University
• Structure of the virus plays a major role in the disease and may help to develop an effective antiviral treatment

A high-resolution structure of the immature Zika virus may provide better understanding of how the virus spreads and infects the host cells, finds a study from the Purdue University. Zika is a mosquito-borne disease that belongs to a group of viruses called flaviviruses. The virus is a mixture of mature, partially mature and immature virus particles.

Michael Rossmann, Purdue’s Hanley Distinguished Professor of Biological Sciences, said, "It is, therefore, probable that the immature form of Zika also plays a role in virus infection and spread."

The research findings were published in the journal Nature Structural & Molecular Biology.

Kuhn, director of the Purdue Institute of Inflammation, Immunology and Infectious Disease "I think these findings open the door to begin to explore the assembly process of the virus."

"We see clear differences between the structure of the immature virus and the mature virus. Not only are there differences in the outer structure, but the inner core must also undergo some significant changes during maturation. We need to study what these changes are and why they occur."

The research team was led by Rossman along with Kuhn. It is also notable that they had earlier led a team last year to study the mature Zika virus.

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The research study on the virus structure may help to develop new antiviral treatments and vaccines.

Cryo-electron microscopy technique was used to reconstruct the immature Zika virus structure at 9 Angstroms resolution.

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The virus genome was housed inside a protective envelope which consists of the lipid membrane, envelope protein, precursor membrane protein and capsid protein.

The research team from Purdue University were the first one to study the position of capsid protein inside the immature Zika virus.

The capsid protein plays a significant role in recognizing the genetic material of the virus and guides the RNA strands into the virus for assembly.

The envelope protein helps in the binding, attachment and fusion into the host cells during infection.

The membrane protein may cleave the mature Zika virus from the host cells to infect other cells.

Details Revealed by the Immature Zika Virus Structure

• The envelope and precursor membrane proteins are arranged in 60 spike-like features on the surface of the virus, whereas in the mature zika virus, membrane protein is covered by the envelope protein.
• Capsid protein is located on the internal side of the lipid membrane.

The study findings were also able to show the differences between immature zika virus and other immature flaviviruses.

Facts on Zika Virus

• Zika virus is transmitted by Aedes mosquitos.
• ZIka virus outbreaks have been recorded in Africa, America, Asia and the Pacific.
• The mosquito-borne flavivirus was first identified in monkeys (Uganda 1947).
• In 2015, an association between Zika virus and Guillan-Barre syndrome that leads to temporary paralysis was reported in Brazil.
• Zika virus is usually diagnosed in patients with suspected symptoms and recent history of travel to countries where the Zika virus transmission is active.
• Currently, there is no vaccine for Zika virus.

References

1. Vidya Mangala Prasad, Andrew S Miller,Thomas Klose, Devika Sirohi,Geeta Buda,Wen Jiang, Richard J Kuhn & Michael G Rossmann, Structure of the immature Zika virus at 9 Å resolution, Nature Structural & Molecular Biology,(2017); DOI:10.1038/nsmb.3352
2. About Zika - (https://www.cdc.gov/zika/about/)
3. Zika virus - (http://www.who.int/mediacentre/factsheets/zika/en/)

Source-Medindia