Functional assessment of European sea bass RTP3 proteins and their effect on RGNNV replication

Area of Science:

• Aquatic immunology
• Molecular biology
• Fish disease

Background:

• RTP3 proteins are implicated in European sea bass innate immunity against NNV infections.
• The precise mechanisms of RTP3 protein action in antiviral defense remain largely unknown.

Purpose of the Study:

• To comprehensively investigate the anti-RGNNV activity of European sea bass RTP3 X1 and RTP3 X2 proteins.
• To explore potential mechanisms underlying the antiviral or pro-viral effects of these RTP3 variants.

Main Methods:

• Cloning of sea bass rtp3 X1 and rtp3 X2 ORFs into expression vectors.
• Transfection of E-11 cell lines for stable expression of RTP3 X1 and/or RTP3 X2.
• Analysis of gene expression (mx, tnf-α), cellular tolerance to oxidative stress, and apoptosis induction.

Main Results:

• RTP3 X2 demonstrated antiviral activity, whereas RTP3 X1 displayed a pro-viral effect in E-11 cells.
• Both RTP3 X1 and RTP3 X2 suppressed the induction of mx and tnf-α genes.
• Enhanced cellular tolerance to oxidative stress was observed, particularly in RTP3 X1-expressing cells.
• RTP3 X1 promoted apoptosis in non-infected cells, suggesting its role in the pro-viral effect.

Conclusions:

• European sea bass RTP3 X1 and RTP3 X2 are versatile proteins influencing multiple cellular functions.
• Apoptosis and oxidative stress tolerance are likely involved in the pro-viral effect of RTP3 X1.
• These findings provide a foundation for further research into the mechanisms of RTP3-mediated immune modulation in fish.