1. Molecular characterization of Pacific oyster (Crassostrea gigas) IRAK4 gene and its role in MyD88-dependent pathway.
- Author
-
Tang, Xueying, Huang, Baoyu, Zhang, Linlin, Li, Li, and Zhang, Guofan
- Subjects
- *
INTERLEUKIN-1 receptors , *PACIFIC oysters , *MOLLUSK genetics , *MOLLUSK phylogeny , *IMMUNOPRECIPITATION - Abstract
Interleukin-1 receptor-associated kinases (IRAKs) play important roles in MyD88-dependent TLR signaling, the crucial innate immune pathway in molluscs. In this study, we examined the full-length IRAK4 genetic sequence in the Pacific oyster ( Crassostrea gigas ) by molecular cloning. Phylogenetic analysis revealed that CgIRAK4 is most closely related to Mytilus edulis , and forms a clade with other molluscs. CgIRAK4 transcripts are widely expressed in all tissues, with the highest expression observed in the hemocytes and gill. Moreover, CgIRAK4 is significantly upregulated after Oyster herpesvirus-1 microvariant (OsHV-1 μvar), Vibrio alginolyticus , and poly I:C challenge. Yeast two-hybrid and co-immunoprecipitation assays reveal that the CgIRAK4 death domain is necessary to mediate interaction between CgIRAK4 and two CgMyD88 isoforms. In addition, CgIRAK4 overexpression cannot induce NF-κB transcriptional activity, but blocks that induced by CgMyD88 in HEK293T cells. These findings elucidate the mechanisms of MyD88-dependent TLR signaling in molluscs, and the differences in IRAK-mediated pathway activation between invertebrates and vertebrates. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF