Shrimp pmo-miR-750 regulates the expression of sarcoplasmic calcium-binding protein facilitating virus infection in Penaeus monodon

Area of Science:

• * Molecular Biology
• * Marine Biology
• * Virology

Background:

• * MicroRNAs (miRNAs) are key regulators of gene expression, particularly in antiviral responses.
• * Penaeus monodon miR-750 (pmo-miR-750) is upregulated during white spot syndrome virus (WSSV) infection, but its role is unknown.
• * Understanding miRNA functions is crucial for developing strategies against viral diseases in shrimp aquaculture.

Purpose of the Study:

• * To investigate the function of pmo-miR-750 in WSSV-infected shrimp.
• * To identify the target genes regulated by pmo-miR-750.
• * To elucidate the role of pmo-miR-750 in WSSV pathogenesis and shrimp immune response.

Main Methods:

• * Two-dimensional gel electrophoresis to identify protein targets of pmo-miR-750 mimic injection.
• * In vitro validation of pmo-miR-750 binding to target mRNA.
• * Quantitative analysis of gene expression and viral load (WSSV copy number) using RNA interference (RNAi) and miRNA mimics.
• * Apoptosis assays in hemocytes.

Main Results:

• * Sarcoplasmic calcium-binding protein (Scp) and actin1 (Act1) were identified as downregulated proteins after pmo-miR-750 mimic injection.
• * pmo-miR-750 directly binds to Scp mRNA, leading to translational suppression.
• * In WSSV-infected shrimp, pmo-miR-750 mimic injection or Scp knockdown increased WSSV copy number and decreased survival.
• * Scp knockdown induced apoptosis in hemocytes during WSSV infection.

Conclusions:

• * Upregulated pmo-miR-750 suppresses Scp expression at both transcript and protein levels during the late stage of WSSV infection.
• * The pmo-miR-750/Scp interaction modulates apoptosis and facilitates WSSV propagation in Penaeus monodon.
• * pmo-miR-750 plays a detrimental role in shrimp antiviral defense by targeting Scp.