CD-loop Extension in Zika Virus Envelope Protein Key for Stability and Pathogenesis

Area of Science:

• Virology
• Structural Biology
• Immunology

Background:

• Zika virus (ZIKV) causes severe congenital malformations and neurological disorders, posing a significant public health challenge.
• Structural differences in the ZIKV envelope protein, specifically the extended CD-loop and hydrogen-bonding network, may explain its enhanced stability compared to related flaviviruses.
• This enhanced stability is hypothesized to contribute to ZIKV's increased infectivity, disease severity, and persistence.

Purpose of the Study:

• To investigate the functional role of the ZIKV envelope protein's extended CD-loop and hydrogen-bonding network in viral infection and pathogenesis.
• To generate and characterize ZIKV recombinant viruses with specific mutations in these motifs.

Main Methods:

• Generation of ZIKV recombinant viruses with disrupted hydrogen-bonding networks (350A, 351A, 350A/351A) and a deleted CD-loop extension (Δ346).
• Assessment of viral replication, virion stability, and pathogenesis in cell culture and in vivo models.
• Evaluation of the antigenicity of the Δ346 mutant compared to wild-type ZIKV.

Main Results:

• The extended CD-loop of ZIKV plays a critical role in cell-type-dependent viral replication.
• Disruption of the CD-loop extension (Δ346 mutant) significantly impacts virion stability and in vivo pathogenesis.
• The Δ346 mutant exhibits antigenicity comparable to the wild-type ZIKV.

Conclusions:

• The extended CD-loop is a crucial determinant of ZIKV's infectivity and disease-causing potential.
• The Δ346 mutant represents a promising candidate for a live-attenuated vaccine platform due to its attenuated pathogenesis and preserved antigenicity.
• This research provides insights into flavivirus stability and offers a potential strategy for ZIKV vaccine development.