Thioredoxin domain-containing protein 12 (TXNDC12) in red spotted grouper (Epinephelus akaara): Molecular characteristics, disulfide reductase activities, and immune responses

by Selleckchem | Dec 18 2023

Thioredoxins are small ubiquitous redox proteins that are involved in many biological processes. Proteins with thiol-disulfide bonds are essential regulators of cellular redox homeostasis and diagnostic markers for redox-dependent diseases. Here, we identified and characterized the thioredoxin domain-containing protein 12 (EaTXNDC12) gene in red spotted grouper (Epinephelus akaara), evaluated transcriptional responses, and investigated the activity of the recombinant protein using functional assays. EaTXNDC12 is a 19.22-kDa endoplasmic reticulum (ER)-resident protein with a 522-bp open reading frame and 173 amino acids, including a signal peptide. We identified a conserved active motif (66WCGAC70) and ER retention motif (170GDEL173) in the EaTXNDC12 amino acid sequence. Relative EaTXNDC12 mRNA expression was analyzed using 12 different tissues, with the highest expression seen in brain tissue, while skin tissue showed the lowest expression level. Furthermore, mRNA expression in response to immune challenges was analyzed in the head kidney, blood, and gill tissues. EaTXNDC12 was significantly modulated in response to bacterial endotoxin lipopolysaccharide (LPS), nervous necrosis virus (NNV), and polyinosinic:polycytidylic acid (poly(I:C)) challenges in all of the tested tissues. Recombinant EaTXNDC12 (rEaTXNDC12) displayed antioxidant ability in an insulin reductase assay, and a capacity for free radical inhibition in a 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay. In addition, a DNA nicking assay revealed that purified rEaTXNDC12 exhibited concentration-dependent DNA protection activity, while results from 2-hydroxyethyl disulfide and L-dehydroascorbic assays indicated that rEaTXNDC12a possesses reducing ability. Furthermore, fathead minnow (FHM) cells transfected with EaTXNDC12-pcDNA demonstrated significantly upregulated cell survival against H2O2-induced apoptosis. Collectively, the results of this study strengthen our knowledge of EaTXNDC12 with respect to cellular redox hemostasis and immune regulation in Epinephelus akaara.

Comments:

Thank you for sharing this detailed information about the identification and characterization of the thioredoxin domain-containing protein 12 (EaTXNDC12) gene in red spotted grouper (Epinephelus akaara). This study provides valuable insights into the role of EaTXNDC12 in cellular redox homeostasis, immune regulation, and antioxidant activities in the species.

The findings suggest that EaTXNDC12 is an important player in the redox regulation of biological processes, as evidenced by its involvement in antioxidant and free radical inhibition activities. The study also highlights the modulation of EaTXNDC12 expression in response to immune challenges, indicating its role in the immune response of the red spotted grouper. Additionally, the ability of recombinant EaTXNDC12 to protect DNA and enhance cell survival against apoptosis further underscores its significance in maintaining cellular integrity and function, particularly under oxidative stress conditions.

Overall, this research contributes to our understanding of the molecular mechanisms underlying redox homeostasis and immune responses in fish species, and it may have implications for studying similar processes in other organisms. If you have any specific questions or if there's anything else you would like to know about this topic or any other topic, feel free to ask!