title: Molecular characterization and expression analysis of an inhibitor of NF-κB (IκB) from Asiatic hard clam Meretrix meretrix.
abstract: Inhibitor of NF-κB (IκB) is an important member of Rel/NF-κB signaling pathway, which is an important mediator of immune responses in innate immune system. In this study, the IκB cDNA of hard clam Meretrix meretrix (designated as Mm-IκB) was cloned and characterized. The full-length cDNA of Mm-IκB was of 2098 bp, containing a 5' untranslated region (UTR) of 123 bp, a 3' UTR of 810 bp with a poly (A) tail, and an open reading frame (ORF) of 1164 bp encoding a polypeptide of 387 amino acids. The high similarity of Mm-IκB with other IκBs from invertebrates indicated that Mm-IκB should be a member of IκB family. Similar to most IκBs, Mm-IκB possessed all conserved features critical for the fundamental structure and function of IκBs, such as five ankyrin repeats and a conserved degradation motif (DS(44)RYSS(48)). Two PEST domains and a phosphorylation site motif (S(367)EEE(370)) at the C-terminus of Mm-IκB were identified. By quantitative real-time RT-PCR analysis, mRNA level of Mm-IκB was found to be most abundantly expressed in the tissues of mantle, gill and hepatopancreas, weakly expressed in muscle, foot and haemocyte. The Mm-IκB gene expression was significantly up-regulated at 24 h in haemocyte and at 12 h in gill after Vibrio anguillarum challenge, respectively. The results suggested the involvement of Mm-IκB in response against bacterial infection and further highlighted its functional importance in the immune system of M. meretrix.
authors.affiliation: National Marine Environmental Monitoring Center, Dalian, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Hongjun
authors.initials: H
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049872:Bivalvia / Q000378:metabolism*; D003001:Cloning, Molecular; D005786:Gene Expression Regulation / Q000502:physiology*; D005880:Gills / Q000378:metabolism; D006434:Hemocytes; D020672:I-kappa B Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D020672:I-kappa B Proteins