Cloning and characterization of two different ficolins from the giant freshwater prawn Macrobrachium rosenbergii
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Xiao-Wen Zhang1, Xian-Wei Wang2, Ying Huang3
1School of Life Science, Henan Normal University, Xinxiang, Henan 453007, China.
Abstract:
Ficolins, a kind of lectin containing collagen-like and fibrinogen-related domains (FReDs, also known as FBG or FREP), are involved in the first line of host defense against pathogens. In this study, two ficolins, namely, MrFico1 and MrFico2, from the giant freshwater prawn Macrobrachium rosenbergii were identified. In contrast to other ficolins, these two ficolins have no collagen-like domain, but such ficolins contain a coiled region and a FReD domain. Phylogenetic analysis showed that MrFico1 and MrFico2, together with two ficolin-like proteins from Pacifastacus leniusculus, belonged to one group. Quantitative RT-PCR (qRT-PCR) showed that both MrFico1 and MrFico2 were expressed in hepatopancreas, stomach and intestine, with the highest expression in stomach for MrFico1, compared to the highest expression in hepatopancreas for MrFico2. qRT-PCR analysis also showed that MrFico1 was obviously upregulated upon Vibrio anguillarium challenge, while MrFico2 was upregulated after challenged by V. anguillarium or white spot syndrome virus. Bacterium-binding experiment showed that MrFico1 and MrFico2 could bind to different microbes, and sugar-binding assay revealed that these two ficolins could also bind to lipopolysaccharide and peptidoglycan, the glycoconjugates of bacteria surface. Moreover, these two ficolins could agglutinate bacteria in a calcium-dependent manner, and the results of bacteria clearance experiment showed that both ficolins could facilitate the clearance of injected bacteria in the prawn. Our results suggested that MrFico1 and MrFico2 may function as pattern-recognition receptors in the immune system of M. rosenbergii.
Insights
Two novel ficolins, MrFico1 and MrFico2, were identified in the giant freshwater prawn Macrobrachium rosenbergii. These ficolins play a role in host defense by binding microbes and facilitating bacterial clearance.
Area of Science:
- * Invertebrate immunology
- * Molecular biology
- * Crustacean aquaculture
Background:
- * Ficolins are lectins crucial for innate immunity, recognizing pathogens via collagen-like and fibrinogen-related domains (FReDs).
- * The giant freshwater prawn Macrobrachium rosenbergii possesses a complex immune system, yet the specific roles of ficolins remain underexplored.
Purpose of the Study:
- * To identify and characterize novel ficolin genes (MrFico1 and MrFico2) in M. rosenbergii.
- * To investigate the expression patterns and immune functions of these ficolins in response to bacterial challenges.
Main Methods:
- * Gene identification and phylogenetic analysis.
- * Quantitative reverse transcription PCR (qRT-PCR) for gene expression analysis.
- * Bacterial binding, sugar-binding, agglutination, and bacterial clearance assays.
Main Results:
- * Two ficolins, MrFico1 and MrFico2, lacking collagen-like domains but possessing coiled and FReD domains, were identified and phylogenetically grouped with ficolin-like proteins.
- * Both MrFico1 and MrFico2 were expressed in the hepatopancreas, stomach, and intestine, with differential expression patterns observed.
- * MrFico1 and MrFico2 exhibited calcium-dependent binding to various microbes, including lipopolysaccharide and peptidoglycan, and enhanced bacterial clearance in vivo.
Conclusions:
- * MrFico1 and MrFico2 represent novel ficolins in M. rosenbergii, distinct from typical ficolins due to the absence of collagen-like domains.
- * These ficolins are integral components of the prawn's innate immune system, functioning as pattern-recognition receptors involved in pathogen recognition and elimination.
- * The findings contribute to understanding crustacean immunity and may inform strategies for disease management in aquaculture.
