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Published on: April 22, 2019
Molecular cloning and functional characterization of a QM protein in large yellow croaker (Larimichthys crocea)
Fang Han1, Shijun Xiao1, Yu Zhang1
1Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen 361021, PR China.
Abstract:
Since it was proposed to be a tumor suppressor in 1991, QM protein has attracted intensive and wide attention in plants, animals and fungi research fields. Up to date, however, the function of QM protein in fish immunity remains unknown. In this investigation, a QM gene (named as LycQM gene) was cloned from large yellow croaker (Larimichthys crocea), and LycQM protein was expressed in Escherichia coli and purified. The LycQM gene was ubiquitously transcribed in multi-tissues, including spleen, muscle, heart, liver, intestine, blood and head kidney. By quantitative real-time RT-PCR analysis, we found the highest and the lowest expression level of LycQM gene in head kidney and in heart, respectively. Time course analysis showed that LycQM expression was obviously up-regulated in blood and head kidney after immunization with polyinosinic polycytidynic acid (poly I:C), formalin-inactive Gram-negative bacterium Vibrio parahaemolyticus and bacterial lipopolysaccharides (LPS). Moreover, as demonstrated by RNAi assays, LycQM protein could regulate the activity of phenoloxidase, a key enzyme in the proPO activation system of immunity. These results suggested that LycQM protein might play an important role in the immune response against microorganisms in large yellow croaker.
Insights
The QM protein, previously known as a tumor suppressor, is investigated in fish immunity. This study reveals its crucial role in the large yellow croaker
Area of Science:
- Aquatic immunology
- Molecular biology
- Fish disease resistance
Background:
- QM protein, identified as a tumor suppressor in 1991, has been studied in various organisms.
- Its function in fish immunity, however, remains largely unexplored.
- Understanding QM protein's role is vital for advancing aquaculture health and disease management.
Purpose of the Study:
- To clone and characterize the QM gene (LycQM) from large yellow croaker (Larimichthys crocea).
- To investigate the expression patterns and immune-responsive regulation of LycQM in fish.
- To elucidate the role of LycQM protein in the fish immune system.
Main Methods:
- Cloning of the LycQM gene and expression of LycQM protein in Escherichia coli.
- Quantitative real-time RT-PCR to analyze gene expression across multiple tissues.
- Immune challenge experiments using polyinosinic polycytidynic acid (poly I:C), Vibrio parahaemolyticus, and lipopolysaccharides (LPS).
- RNA interference (RNAi) assays to assess LycQM's functional role in immunity.
Main Results:
- The LycQM gene is ubiquitously transcribed in various tissues, with the highest expression in head kidney and lowest in heart.
- LycQM expression significantly increased in blood and head kidney following immune stimulation.
- RNAi assays demonstrated that LycQM protein regulates phenoloxidase activity, a key component of the proPO immune system.
Conclusions:
- LycQM protein is widely distributed in large yellow croaker tissues.
- Its expression is modulated by immune challenges, indicating a role in immune response.
- LycQM protein is implicated in regulating the phenoloxidase system, suggesting its importance in fish immunity against pathogens.
