Atlantic salmon type I interferon genes revisited

Area of Science:

• Immunology
• Genomics
• Aquaculture

Background:

• Type I interferons (IFN-I) are crucial for innate immunity in vertebrates against viral pathogens.
• Previous genomic data on Atlantic salmon IFN-I genes were limited.

Purpose of the Study:

• To comprehensively analyze the Type I interferon gene repertoire in an updated Atlantic salmon genome (Ssal_v3.1).
• To investigate the expression patterns and antiviral functions of Atlantic salmon IFN-I genes following viral mimic stimulation.

Main Methods:

• Genome analysis of the Ssal_v3.1 assembly to identify and characterize IFN-I genes.
• Quantitative analysis of IFN-I gene expression in Atlantic salmon tissues (heart, head kidney) after poly I:C stimulation.
• Functional assessment of antiviral activity using cell-based assays and measurement of Mx1 gene expression in fish.

Main Results:

• Identification of 47 IFN-I genes across multiple chromosomes, including novel IFNe and IFNf genes.
• Poly I:C stimulation significantly upregulated IFNc, IFNe, and IFNf genes, with tissue-specific expression patterns.
• IFNc genes demonstrated potent antiviral activity, providing full protection to cells and inducing Mx1 gene expression, while IFNe and IFNf showed moderate effects.

Conclusions:

• Atlantic salmon possess a diverse and expanded repertoire of Type I interferon genes.
• Specific interferon subtypes, particularly IFNc, play a significant role in conferring robust antiviral immunity in Atlantic salmon.
• This study enhances our understanding of the innate immune defenses in Atlantic salmon, crucial for aquaculture and fish health.