Multiple gene and transcript variants encoding trout C-polysaccharide binding proteins are differentially but strongly induced after infection with Aeromonas salmonicida.
Two 'trout C-polysaccharide-binding proteins,' TCBP1 and -2, with relevance to early inflammatory events have been discovered in the last century. The present study characterises the respective cDNA sequences from rainbow trout (Oncorhynchus mykiss), including multiple TCBP1 transcript variants. These variants are generated either by the use of alternative splice sites or the exclusion of exons. The longest mRNA isoform, TCBP1-1, encodes a 245-aa protein with a large signal peptide and a complement component C1q domain. The shortest mRNA isoform, TCBP1-5, contains a premature termination codon and hence fails to encode a functional factor. The 224-aa-long TCBP2 protein consists of a comparably shorter signal peptide and a pentraxin domain. Evolutionary analyses clearly separated TCBP1 and -2 because of distinctive protein motifs. Expression profiling in the liver, spleen, and head kidney tissues of healthy trout revealed that TCBP2 mRNA concentrations were higher than the concentrations of all five TCBP1 mRNA isoforms together. The hepatic levels of these TCBP1 variants increased significantly upon infection with Aeromonas salmonicida, whereas TCBP2 transcript levels rose moderately. As the biological function of TCBP1 is barely understood, we tagged this factor with the green fluorescent protein and visualised its expression in HEK-293 cells. Overexpression of TCBP1 increased the level of active NF-κB factors and induced cell death, indicating its involvement in proapoptotic NF-κB-dependent signalling routes.
Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
Judith M
JM
Köbis
Rostock University Medical Center, Department of Cell Biology, Schillingallee 69, 18057 Rostock, Germany.
Henrike
H
Rebl
Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
Tom
T
Goldammer
Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany. Electronic address: rebl@fbn-dummerstorf.de.
Alexander
A
Rebl
D048409:Aeromonas salmonicida / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005667:Furunculosis / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D005786:Gene Expression Regulation / Q000276:immunology*; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D007113:Immunity, Innate; D017686:Oncorhynchus mykiss; D010802:Phylogeny; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D015398:Signal Transduction
D018076:DNA, Complementary; D029941:Fish Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C055213:saccharide-binding proteins
Acute phase; Complement component; Innate immunity; Pentraxin; TCBP; Teleost