title: Identification and expression of a putative LPS-induced TNF-α factor from Asiatic hard clam Meretrix meretrix.
abstract: LPS-induced TNF-α (LITAF) is a novel transcriptional factor that mediates the expression of inflammatory cytokines in LPS-induced processes. In the present study, the full-length cDNA encoding LITAF (designated as Mm-LITAF) was identified from Asiatic hard clam, Meretrix meretrix, by expressed sequence tag and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of Mm-LITAF was 1653 bp, consisting of a 5' untranslated region (UTR) of 91 bp, a 3'UTR of 1166 bp with one cytokine RNA instability motif (ATTTA) and one polyadenylation signal (AATAAA), and an open reading frame (ORF) of 396 bp encoding a polypeptide of 131 amino acids with a theoretical isoelectric point of 7.49, and predicted molecular weight of 14.47 kDa. The deduced amino acid of Mm-LITAF shared 29-63% similarity with the LITAFs from other species, indicating that Mm-LITAF should be a member of the LITAF family. Two highly conserved CXXC motifs forming a compact Zn(2+)-binding structure were also identified in Mm-LITAF. A quantitative reverse transcriptase real-time PCR (qRT-PCR) assay was developed to assess the expression of Mm-LITAF mRNA in different tissues, and the temporal expression of Mm-LITAF in clams challenged with Vibrio anguillarum. The mRNA transcript of Mm-LITAF could be detected in all the examined tissues with the highest expression level in the gill. Mm-LITAF expression was up-regulated significantly at 16 h in the gill and at 8 h in haemocytes after bacterial challenge, respectively. These results suggest that the Mm-LITAF is a constitutive and inducible acute-phase protein that perhaps involved in the innate immune response of hard clam.
authors.affiliation: Liaoning Key Laboratory of Marine Fishery Molecular Biology, Liaoning Ocean and Fishery Science Institute, Dalian 116023, China.
authors.forename: Hong-Jun
authors.initials: HJ
authors.lastname: Li
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang
authors.forename: Xiang-Gang
authors.initials: XG
authors.lastname: Gao
authors.forename: Hao
authors.initials: H
authors.lastname: Su
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.forename: Chong-Bo
authors.initials: CB
authors.lastname: He
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049872:Bivalvia / Q000235:genetics* / Q000382:microbiology; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D020224:Expressed Sequence Tags; D040461:Gene Components; D005880:Gills / Q000378:metabolism; D006434:Hemocytes / Q000378:metabolism; D008070:Lipopolysaccharides; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha