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Activation of PmRelish from Penaeus monodon by yellow head virus
Suwattana Visetnan1, Premruethai Supungul2, Ikuo Hirono3
1Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Phyathai Road, Bangkok 10330, Thailand.
Abstract:
Humoral innate immune response against pathogenic infection is partly responsible by the Imd pathway in which a transcription factor Relish relays the infection signals to the nuclei for the expression of antimicrobial proteins. A PmRelish gene which encoded a protein of 1195 amino acids was cloned. The PmRelish was constitutively expressed in all tissues tested and mostly up-regulated upon YHV infection. In hemocytes, the PmRelish expression was up-regulated upon Vibrio harveyi, yellow head virus (YHV) and white spot syndrome virus (WSSV) challenges. Using dsRNA silencing of PmRelish gene, it was shown that the expression of penaeidin5 but not anti-lipopolysaccharide factor ALFPm3, crustinPm1 and penaeidin3 was under the regulation of Imd pathway. Under PmRelish silencing, the shrimp were more susceptible to infection by YHV with the 50% survival rate reduced from about 72 h to 42 h. The PmRelish was detected in the cytoplasm of all the hemocytes from both uninfected and YHV-infected shrimp. The accumulation of activated PmRelish in the nuclei was not clearly observed but the activated PmRelish was detected in the YHV-infected hemocytes by Western blot analysis. Thus, the PmRelish and, hence, the Imd pathway respond to the YHV infection.
Insights
The Imd pathway, crucial for shrimp immunity, involves the PmRelish protein. Silencing PmRelish increases susceptibility to Yellowhead virus (YHV) infection, highlighting its role in antiviral defense.
Area of Science:
- Innate immunity
- Molecular biology
- Shrimp aquaculture
Background:
- The Imd pathway is vital for innate immune responses against pathogens.
- Relish acts as a transcription factor, relaying infection signals for antimicrobial protein expression.
- Understanding shrimp immune pathways is crucial for disease management in aquaculture.
Purpose of the Study:
- To clone and characterize the PmRelish gene in shrimp.
- To investigate the role of PmRelish in the Imd pathway and its response to Yellowhead virus (YHV) infection.
- To determine the effect of PmRelish silencing on shrimp susceptibility to YHV.
Main Methods:
- Cloning of the PmRelish gene.
- Quantitative gene expression analysis (up-regulation upon infection).
- dsRNA silencing of PmRelish and subsequent challenge with YHV.
- Western blot analysis to detect activated PmRelish.
Main Results:
- PmRelish gene cloned, encoding a 1195-amino acid protein.
- PmRelish is constitutively expressed and up-regulated by YHV infection in shrimp tissues and hemocytes.
- PmRelish silencing specifically affects penaeidin5 expression, not other antimicrobial proteins.
- PmRelish silencing significantly reduces shrimp survival rates upon YHV challenge.
- Activated PmRelish detected in YHV-infected hemocytes, though nuclear accumulation is unclear.
Conclusions:
- PmRelish plays a significant role in the Imd pathway-mediated immune response against YHV in shrimp.
- The Imd pathway, through PmRelish, is activated in response to YHV infection.
- PmRelish is essential for shrimp defense against YHV, and its silencing leads to increased susceptibility.
