Genomics of fish cytokines

Area of Science:

• Immunology
• Aquaculture
• Genomics

Background:

• Cytokines regulate immune systems, with fish cytokine discovery crucial for aquaculture applications like vaccines and immunostimulants.
• Low sequence identity compared to mammals historically hindered fish cytokine identification.
• Early fish cytokine identification was limited to a few key genes like IL-1beta and TNF-alpha.

Purpose of the Study:

• To accelerate the discovery and characterization of fish cytokine genes.
• To leverage conserved synteny between fish and human genomes for efficient gene identification.
• To compare the diversity and types of fish cytokines with their mammalian counterparts.

Main Methods:

• Utilized genome databases of pufferfish (Fugu rubripes, Tetraodon nigroviridis) and zebrafish (Danio rerio) for cytokine gene searches.
• Employed comparative genomics, exploiting syntenic regions between fish and human genomes.
• Bioinformatic analysis to identify and classify cytokine gene families.

Main Results:

• Accelerated discovery of numerous fish cytokine genes following genome sequencing of pufferfish and zebrafish.
• Identified pro-inflammatory cytokines (TNF's, IL-6, IL-17 family), T(H)1 type interleukins (IL-2, IL-15, IL-12alpha, IL-12beta, IL-18), and IL-10 family members (IL-10, IL-19/20, IL-22, IL-26).
• Discovered novel TNF genes and interferon genes; noted the absence of T(H)2 cytokines (IL-4, IL-5, IL-13) and IL-3, IL-7, IL-9.

Conclusions:

• Fish cytokine gene discovery has significantly advanced due to genome sequencing initiatives.
• The identified fish cytokine repertoire shows remarkable similarity in type and diversification to mammals.
• Further research is needed to identify the remaining T(H)2 and other cytokine families in fish.