A murrel interferon regulatory factor-1: molecular characterization, gene expression and cell protection activity

Abstract

In this study, we have reported a first murrel interferon regulatory factor-1 (designated as Murrel IRF-1) which is identified from a constructed cDNA library of striped murrel Channa striatus. The identified sequence was obtained by internal sequencing method from the library. The Murrel IRF-1 varies in size of the polypeptide from the earlier reported fish IRF-1. It contains a DNA binding domain along with a tryptophan pentad repeats, a nuclear localization signal and a transactivation domain. The homologous analysis showed that the Murrel IRF-1 had a significant sequence similarity with other known fish IRF-1 groups. The phylogenetic analysis exhibited that the Murrel IRF-1 clustered together with IRF-1 members, but the other members including IRF-2, 3, 4, 5, 6, 7, 8, 9 and 10 were clustered individually. The secondary structure of Murrel IRF-1 contains 27% α-helices (85 aa residues), 5.7% β-sheets (19 aa residues) and 67.19% random coils (210 aa residues). Furthermore, we predicted a tertiary structure of Murrel IRF-1 using I-Tasser program and analyzed the structure on PyMol surface view. The RNA structure of the Murrel IRF-1 along with its minimum free energy (-284.43 kcal/mol) was also predicted. The highest gene expression was observed in spleen and its expression was inducted with pathogenic microbes which cause epizootic ulcerative syndrome in murrels such as fungus, Aphanomyces invadans and bacteria, Aeromonas hydrophila, and poly I:C, a viral RNA analog. The results of cell protection assay suggested that the Murrel IRF-1 regulates the early defense response in C. striatus. Moreover, it showed Murrel IRF-1 as a potential candidate which can be developed as a therapeutic agent to control microbial infections in striped murrel. Overall, these results indicate the immune importance of IRF-1, however, the interferon signaling mechanism in murrels upon infection is yet to be studied at proteomic level.

Molecular characterization and expression analysis of eleven interferon regulatory factors in half-smooth tongue sole, Cynoglossus semilaevis

“…Previous studies in fish showed that IRF1 and IRF2 were significantly upregulated after stimulation with poly I:C, viral haemorrhagic septicemia virus, and bacteria [38,62,79]. Similarly, in our study, IRF1 and IRF2X1 expressions were significantly upregulated by experimental challenge with both bacteria and virus.…”

Innate and adaptive immune molecules of striped murrel Channa striatus

“…Arockiaraj et al . (, , ,b) observed that A. hydrophila induces the immune system of C. striatus significantly. Different species such as A. veroni , A. hydrophila and A. sobria have been reported from EUS‐infected fish tissues.…”

“…Previous study has reported that it is actively involved in the innate immune system of C. striatus (Arockiaraj et al . ).…”

“…Many immune molecules from C. striatus including interferon regulatory factor‐1 (IRF‐1) (Arockiaraj et al . ), B‐cell lymphocyte 2 (BCL‐2) (Arockiaraj et al . ) and C4CC chemokine 1 (Bhatt et al .…”

“…During prolonged infection, the bacterial pathogen enters the blood stream and results in septicaemia condition (Austin & Adams 1996;Gosling 1996;Roberts 1997;Nielsen et al 2001). Arockiaraj et al (2013Arockiaraj et al ( , 2014aArockiaraj et al ( , 2015a observed that A. hydrophila induces the immune system of C. striatus significantly. Different species such as A. veroni, A. hydrophila and A. sobria have been reported from EUSinfected fish tissues.…”