Identification and expression analysis of IκB and NF-κB genes from Cyclina sinensis

With the increasing economic importance of Cyclina sinensis aquaculture, interest in its defense mechanisms against pathogenic infection has grown in recent years. Inhibitor of nuclear factor-kappaB (I kappa B) and nuclear factor-kappaB (NF-kappa B) are proteins with central roles in many important physiological and pathological processes, such as innate immune responses. In this study, we identified CsI kappa B and CsNF-kappa B genes from a C. sinensis transcriptome library. In healthy adult clams, CsI kappa B and CsNF-kappa B genes were widely expressed in various tissues and highly expressed in hemocytes. Further, the expression levels of these genes were significantly increased in hemocytes challenged by Vibrio anguillarum, Micrococcus luteus and poly I:C. Inhibition of CsMyD88 expression by RNAi technology significantly altered the mRNA expression patterns of CsI kappa B and CsNF-kappa B as measured using quantitative real-time PCR. These results collectively indicated that the NF-kappa B signaling pathway, including CsI kappa B and CsNF-kappa B genes, might be involved in early innate immune responses and may be regulated by a MyD88-dependent signaling pathway in C. sinensis. (C) 2016 Elsevier Ltd. All rights reserved.