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Updated: Mar 20, 2026
Identifying Caspases and their Motifs that Cleave Proteins During Influenza A Virus Infection
Published on: July 21, 2022
Molecular cloning and characterization of four caspases members in Apostichopus japonicus
Yina Shao1, Chenghua Li1, Weiwei Zhang1
1School of Marine Sciences, Ningbo University, Ningbo 315211, PR China.
Abstract:
The caspase family representing aspartate-specific cysteine proteases have been demonstrated to possess key roles in apoptosis and immune response. We previously demonstrated that LPS challenged Apostichopus japonicus coelomocyte could significantly induced apoptosis in vitro. However, apoptosis related molecules were scarcely investigated in this economic species. In the present work, we cloned and characterized four members caspase family from A. japonicus (designated as Ajcaspase-2, Ajcaspase-3, Ajcaspase-6, and Ajcaspase-8, respectively) by RACE. Multiple sequence alignment and structural analysis revealed that all Ajcaspases contained the conservative CASC domain at C terminal, in which some unique features for each Ajcaspase made them different from each other. These specific domains together with phylogenetic analysis supported that all these four identified proteins belonged to novel members of apoptotic signaling pathway in sea cucumber. Tissue distribution analysis revealed that four Ajcaspase genes were constitutively expressed in all examined tissues. The expression of Ajcaspase-2 was tightly correlated with that of Ajcaspase-8 in each detected tissues. Ajcaspase-3 and Ajcaspase-6 transcripts were both highly expressed in immune tissue of coelomocytes. Furthermore, the Vibrio splendidus challenged sea cucumber coelomocytes could significantly up-regulate the mRNA expressions of four genes. The expression levels of Ajcaspase-2 and Ajcaspase-8 were relative earlier than those of Ajcaspase-6 and Ajcaspase-3, respectively, which could be inferred that Ajcapase-2 might directly modulate Ajcaspase-6, and Ajcaspase-8 initiate the expression of Ajcaspase-3. The induce expressions differed among each Ajcaspase depending upon their roles such as initiator or effector caspase. All our results demonstrated that four Ajcaspases present diversified functions in apoptotic cascade signaling pathway of sea cucumber under immune response.
Insights
This study identifies four caspase genes in sea cucumber, revealing their roles in apoptosis and immune responses. These caspases are crucial for the sea cucumber
Area of Science:
- Marine biology
- Molecular biology
- Immunology
Background:
- Caspases are key proteases in apoptosis and immune responses.
- Apoptosis induction by LPS in Apostichopus japonicus coelomocytes was previously shown.
- Apoptosis-related molecules in A. japonicus remain under-investigated.
Purpose of the Study:
- To clone and characterize four caspase family members from A. japonicus.
- To investigate their roles in apoptosis and immune response in sea cucumber.
Main Methods:
- Rapid Amplification of Complementary DNA Ends (RACE) was used for gene cloning.
- Multiple sequence alignment and structural analysis were performed.
- Tissue distribution and gene expression analysis were conducted under immune challenge.
Main Results:
- Four caspase genes (Ajcaspase-2, -3, -6, -8) were identified with conserved CASC domains.
- Phylogenetic analysis confirmed their role in the apoptotic signaling pathway.
- All four genes were constitutively expressed, with higher levels in coelomocytes for Ajcaspase-3 and -6.
- Vibrio splendidus challenge upregulated all four genes, with Ajcaspase-2 and -8 showing earlier induction.
Conclusions:
- The identified Ajcaspases are novel members of the sea cucumber apoptotic pathway.
- They exhibit diverse functions, potentially acting as initiator or effector caspases.
- Ajcaspase-2 and -8 may initiate cascades involving Ajcaspase-6 and -3, respectively.
- These caspases play significant roles in the sea cucumber's immune response and apoptosis.
