Function of the small hydrophobic protein of J paramyxovirus

Area of Science:

• Virology
• Immunology

Background:

• The J paramyxovirus (JPV) genome is exceptionally large for its family, encoding eight genes.
• Understanding the function of JPV's small hydrophobic (SH) protein is crucial for deciphering its pathogenic mechanisms.

Purpose of the Study:

• To investigate the role of the JPV small hydrophobic (SH) protein in viral pathogenesis.
• To determine the effect of SH protein deletion on viral replication, apoptosis, and host immune responses.

Main Methods:

• Construction of a full-length JPV cDNA clone.
• Generation of a recombinant JPV (rJPVΔSH) lacking the SH protein coding sequence.
• Assessment of viral growth, TNF-α production, apoptosis, and NF-κB activation in vitro and in vivo.

Main Results:

• Recombinant JPV lacking the SH protein (rJPVΔSH) replicated similarly to wild-type JPV in cell culture but induced higher levels of tumor necrosis factor alpha (TNF-α).
• rJPVΔSH infection led to increased apoptosis in cell cultures, which was preventable by neutralizing TNF-α antibodies, indicating TNF-α's role in JPV-induced apoptosis.
• JPV SH protein expression inhibited TNF-α-induced NF-κB activation in reporter gene assays, and rJPVΔSH infection in mice resulted in elevated TNF-α expression.

Conclusions:

• The JPV SH protein plays a significant role in suppressing TNF-α production and mitigating virus-induced apoptosis, both in vitro and in vivo.
• JPV SH protein appears to interfere with TNF-α signaling pathways, potentially contributing to viral immune evasion.