Nipah Virus Matrix Protein Influences Fusogenicity and Is Essential for Particle Infectivity and Stability.

Area of Science:

• Virology
• Molecular Biology
• Infectious Diseases

Background:

• Nipah virus (NiV) causes severe, fatal encephalitis in humans.
• Henipaviruses necessitate study in high-containment BSL-4 laboratories, complicating research.
• The role of the matrix (M) protein in NiV replication and particle formation is not fully understood.

Purpose of the Study:

• To investigate the function of the Nipah virus matrix (M) protein in viral life cycle.
• To determine the M protein's role in cell-cell fusion and the formation/release of new viral particles.
• To characterize the impact of M protein deletion on NiV infectivity and particle stability.

Main Methods:

• Generation of a reverse genetics system for NiV strain Malaysia.
• Construction of an M protein-deleted NiV expressing eGFP.
• Analysis of cell-cell fusion, replication kinetics, viral protein release, particle infectivity, and thermostability.

Main Results:

• M protein deletion resulted in slightly increased cell-cell fusion but reduced replication and peak titers.
• Particles produced without M protein showed a >100-fold reduction in infectivity-to-particle ratio.
• M protein-deleted NiV particles were less thermostable and morphologically irregular.

Conclusions:

• The NiV M protein is not essential for producing cell-free virus particles.
• The M protein is critical for the proper assembly and release of stable, infectious NiV particles.
• M protein influences multiple stages of NiV spread, including particle infectivity and stability.