An inhibitor kappa B homologue from bay scallop Argopecten irradians

作者：Mu, Changkao; Yu, Yundong; Zhao, Jianmin; Wang, Lingling^*; Song, Xiaoyan; Zhang, Huan; Qiu, Limei; Song, Linsheng

来源：Fish & Shellfish Immunology, 2010, 28(4): 687-694.

DOI：10.1016/j.fsi.2010.01.005

• Argopecten irradians
• Innate immunity
• Signaling pathway
• NF-kappa B
• I kappa B
• Gene cloning

I kappa B is an important member of NF-kappa B pathway in the innate immune system. In the present study, the full-length cDNA sequence encoding I kappa B protein (designated AiI kappa B) was isolated from bay scallop Argopecten irradians. The complete sequence of AiI kappa B cDNA containing a 5' untranslated region (UTR) of 237 bp, a 3' UTR of 1023 bp with a poly (A) tail, and an open reading frame (ORF) of 1086 bp encoding a polypeptide of 361 amino acids with the predicted molecular weight of 39.9 kDa and theoretical isoelectric point of 4.7. Six ankyrin repeats which were necessary for specific binding to NF-kappa B and two potential phosphorylation sites responsible for I kappa B degradation were identified in the N-terminus of AiI kappa B. No PEST domain but a phosphorylation site motif (S357DSD360) was present at the C-terminus of AiI kappa B. Predicted three-dimensional structure of AiI kappa B shared high similarity with mammalian I kappa B alpha. Similarity and phylogenetic analysis revealed that AiI kappa B was clustered into I kappa Bs from invertebrate. All these typical characteristics indicated that the AiI kappa B should be classified into I kappa B family proteins. Quantitative real-time RT-PCR was employed to assess the mRNA expression of AiI kappa B in various tissues and its temporal expression in haemocytes of scallops challenged with Listonella anguillarum. The mRNA transcript of AiI kappa B could be detected in all the examined tissues with highest expression level in hepatopancreas. Bacteria infection inhibited the transcription level of AiI kappa B. The results suggested the involvement of AiI kappa B in responses against bacterial infection and further highlighted its functional importance in the immune system of A. irradians.

• 出版日期2010-4
• 单位中国科学院海洋研究所; 宁波大学; 西北农林科技大学