Molecular characterization and expression analyses of the Solea senegalensis interferon-stimulated gene 15 (isg15) following NNV infections

• Published in: Fish & shellfish immunology Vol. 66; pp. 423 - 432
• Main Authors: Álvarez-Torres, Daniel, Podadera, Ana María, Alonso, M. Carmen, Bandín, Isabel, Béjar, Julia, García-Rosado, Esther
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2017
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Cloning, Molecular; Cytokines - chemistry; Cytokines - genetics; Cytokines - metabolism; DNA, Complementary - genetics; DNA, Complementary - metabolism; Fish Diseases - genetics; Fish Diseases - immunology; Fish Proteins - chemistry; Fish Proteins - genetics; Fish Proteins - metabolism; Flatfishes; IFN I; isg15 gene; NNV; Nodaviridae - genetics; Nodaviridae - physiology; Phylogeny; RNA Virus Infections - genetics; RNA Virus Infections - immunology; RNA Virus Infections - veterinary; RNA, Messenger - genetics; RNA, Messenger - metabolism; Solea senegalensis; Ubiquitins - chemistry; Ubiquitins - genetics; Ubiquitins - metabolism; Solea senegalensis; NNV; isg15 gene; IFN I
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2017.05.040

Interferons are essential in fish resistance to viral infections. They induce interferon-stimulated genes, such as isg15. In this study, the Senegalese sole isg15 gene (ssisg15) has been characterized. As other isg15, ssisg15 contains a 402-bp intron sited in the 5′-UTR, and the full length cDNA is 1492-bp, including a 480-bp ORF. The expression analyses revealed basal levels of isg15 transcripts, and a clear induction after poly I:C injection, that reached maximum values in brain, head kidney and gills. The ssisg15 induction patterns were similar in RGNNV- and SJNNV-inoculated fish, whereas the reassortant (RG/SJ) isolate, which has higher replication fitness, triggered delayed but higher transcript levels. Furthermore, RG/SJ infection after poly I:C treatment reduced the induction of ssisg15 transcripts, suggesting an antagonistic mechanism against interferon type I system, that might allow an efficient viral replication at the initial steps of the infective process. •Senegalese sole isg15 gene (ssisg15) contains a 402-bp intron in the 5′-UTR.•Maximum levels of ssisg15 transcripts were reached in brain, head kidney and gills after poly I:C induction.•RGNNV/SJNNV induced the highest levels of ssisg15 transcripts with a delayed onset.•The RGNNV/SJNNV isolate reduces poly I:C induced ssisg15 transcript levels.