Ceruloplasmin, a moonlighting protein in fish.

Area of Science:

• Biochemistry
• Evolutionary Biology
• Fish Biology

Background:

• Ceruloplasmin is an ancient multicopper oxidase crucial for oxygen handling in vertebrates.
• Its structure suggests plasticity and multifunctional activity, with conserved copper-binding residues throughout evolution.
• Cupredoxin is considered the evolutionary precursor of ceruloplasmin.

Purpose of the Study:

• To characterize the ceruloplasmin gene in various fish species.
• To investigate the role of ceruloplasmin in fish disease response and physiological conditions.
• To explore ceruloplasmin as a potential marker in fish health management.

Main Methods:

• Comparative gene sequencing and characterization of the ceruloplasmin gene in zebrafish, rohu, medaka, catfish, icefish, goldfish, and yellow perch.
• Analysis of ceruloplasmin gene expression patterns during bacterial and parasitic infections.
• Evaluation of ceruloplasmin's role in inflammatory responses to various toxicities.

Main Results:

• The complete coding sequence of fish ceruloplasmin gene is approximately 3.2 kb, encoding 1000-1100 amino acids.
• Fish ceruloplasmin genes range around 13 kb, comprising 20 exons and 19 introns, with the liver as the primary synthesis site.
• Increased ceruloplasmin gene expression was observed during bacterial infections in catfish and rohu, suggesting a role in disease response and potential as a resistance marker.

Conclusions:

• Ceruloplasmin exhibits conserved structure and function across vertebrate evolution, with significant conservation in fish.
• The gene's expression is linked to bacterial and parasitic infections, hormonal, drug, and heavy metal-induced toxicity in fish.
• Ceruloplasmin acts as a 'moonlighting' protein, adapting its function to various physiological and pathological conditions in fish.