|Milev-Milovanovic, I - U. MISS. MEDICAL CTR.|
|Majji, S - U. MISS. MEDICAL CTR.|
|Thodima, J - UNIV. SOUTHERN MISS.|
|Deng, Y - UNIV. SOUTHERN MISS.|
|Hanson, L - MISS. STATE UNIV.|
|Arnizaut, A - MISS. STATE UNIV.|
|Chinchar, V - U. MISS. MEDICAL CTR.|
Submitted to: Fish and Shellfish Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 17, 2009
Publication Date: May 1, 2009
Citation: Milev-Milovanovic, I., Majji, S., Thodima, J., Deng, Y., Hanson, L., Arnizaut, A., Waldbieser, G.C., Chinchar, V.G. 2009. Identification and Expression Analyses of Poly[I:C]-stimulated Genes in Channel Catfish (Ictalurus punctatus). Fish and Shellfish Immunology 26:811-820. Interpretive Summary: Channel catfish is a commercially important species in North American aquaculture, but a main limit to production is losses to disease. This research was designed to help identify patterns of gene expression in cultured cells in response to a simulated viral infection. A microarray was used to simultaneously measure levels of gene expression using 2500 cDNA probes derived from clones catfish sequences. The results revealed more than 20 genes with increased expression levels after challenge with a viral mimic. The results pointed to an interferon-mediated response, like in mammals, that triggered the appearance of catfish gene products that function individually and collectively to inhibit virus replication. A better understanding of catfish immune mechanisms will help breeders identify superior broodstock for genetic improvement of this species.
Technical Abstract: Channel catfish (Ictalurus punctatus) have proven to be an excellent model with which to study immune responses in lower vertebrates. Identification of antiviral antibodies and cytotoxic cells, as well as both type I and II interferon (IFN), demonstrate that catfish likely mount a vigorous anti-viral immune response. In this report, we focus on other elements of the anti-viral response, and identify more than two dozen genes that are induced following treatment of catfish cells with poly [I:C]. We showed that poly [I:C] induced type I interferon within 2 hr of treatment, and that characteristic interferon stimulated genes (ISGs) appeared 6 - 12 hr after exposure. Among the ISGs detected by RT PCR assay were homologs of ISG15, Mx1, IFN regulatory factor 1 (IRF-1), inhibitor of apoptosis protein-1 (IAP-1) and the chemokine CXCL10. Microarray analyses showed that 13 and 24 cellular genes, respectively, were upregulated in poly[I:C]-treated B cell and fibroblast cultures. Although many of these genes were novel and did not fit the profile of mammalian ISGs, there were several (ISG-15, ubiquitin-conjugating enzyme E2G1, integrin-linked kinase, and clathrin associated protein 47) that were identified as ISGs in mammalian systems. Taken together, these results suggest that like mammals, IFN triggers the appearance of catfish gene products that function individually and collectively to inhibit virus replication.