Analysis of a catfish gene resembling interleukin-8: cDNA cloning, gene structure, and expression after infection with Edwardsiella ictaluri

The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Auburn University, 201 Swingle Hall, Auburn, AL 36849, USA.
Developmental & Comparative Immunology (Impact Factor: 2.82). 02/2005; 29(2):135-42. DOI: 10.1016/j.dci.2004.06.011
Source: PubMed


Chemokines are important mediators for innate immunity involved in recruitment, activation and adhesion of a variety of leukocyte types to inflammatory foci. While almost all chemokines have been identified from mammals, only a handful of fish chemokines have been identified. Here we report molecular cloning, sequence analysis, and expression of a channel catfish gene resembling interleukin-8 (IL-8). The gene has two alternatively spliced transcripts encoding 114 and 111 amino acids, respectively. The gene has four exons and three introns, typical of the CXC chemokine gene organization. In spite of the structural conservation through evolution, the piscine IL-8 genes showed a much greater sequence divergence than their counterparts among mammals. RT-PCR indicated that both spliced forms were expressed. Expression of the IL-8 like gene was up-regulated 3-5-fold in channel catfish and blue catfish after infection with pathogenic bacteria Edwardsiella ictaluri.

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Available from: Peng Xu, Apr 07, 2014
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    • "Phylogenetic tree analysis further confirmed PaCXCL8l to be a member of the fish CXCL8 cluster. Transcripts of fish CXCL8-like proteins are detected in a wide range of tissues (Chen et al., 2005; Li and Yao, 2013; T.T. Wang et al., 2013), and also in macrophages (Baggiolini et al., 1994; Laing et al., 2002). In this study, PaCXCL8l expression was detected in liver, brain, gill, head kidney, heart, and spleen, as well as monocytes/macrophages. "
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    • "This motif is suggested to retain functionality though to a lower extent (Hebert et al., 1991). However, the overall sequence conservation among piscine IL8 genes is low indicating a high degree of molecular diversification (Chen et al., 2005). All teleost species investigated so far encode in common a fish-specific IL8-encoding gene variant, CXCL8_L1 (Corripio-Miyar et al., 2007; Seppola et al., 2008; Laing et al., 2002; Lee et al., 2001). "
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    • "For example, the CXCL13 homologue was shown to be activated by LPS but not polyI:C (Kim et al., 2007) and a trout CXCL9-11 homologue was induced during viral infection and by polyI:C, a known ligand of Toll like receptor 3 (Chaves-Pozo et al., 2010; Montero et al., 2009). Some cytokines are also potent inducers of CXC chemokine expression, as seen with trout interferon gamma (IFN-c) and tumor necrosis factor (TNF)-a that induce CXCL9-11 expression, which is clearly an IFN-c inducible protein (cIP) (Laing et al., 2002; Chen et al., 2010; Zou et al., 2005). CXCL8_L1 and CXCL8_L2 have been produced as recombinant proteins and shown to primarily direct the migration of phagocytes and enhance their respiratory burst activity (RBA) (van der Aa et al., 2010; Harun et al., 2008; Montero et al., 2008). "
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