Insights into molecular profiles and genomic evolution of an IRAK4 homolog from rock bream (Oplegnathus fasciatus): Immunogen- and pathogen-induced transcriptional expression. Issue 2 (April 2015)

• Record Type: Journal Article
• Authors: Umasuthan, Navaneethaiyer; Bathige, S.D.N.K.; Whang, Ilson; Lim, Bong-Soo; Choi, Cheol Young; Lee, Jehee
• Is Part Of: Fish & shellfish immunology. Volume 43:Issue 2(2015:Apr.)
• Page Start: 436
• Page End: 448
• Publication Date: 2015-04
• Subjects: Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2014.12.010
• Languages: English
• ISSNs: 1050-4648

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010">As a pivotal signaling mediator of toll-like receptor (TLR) and interleukin (IL)-1 receptor (IL-1R) signaling cascades, the IL-1R-associated kinase 4 (IRAK4) is engaged in the activation of host immunity. This study investigates the molecular and expressional profiles of an <italic>IRAK4-like</italic> homolog from <italic>Oplegnathus fasciatus</italic> (<italic>OfIRAK4</italic>). The <italic>OfIRAK4</italic> gene (8.2 kb) was structured with eleven exons and ten introns. A putative coding sequence (1395 bp) was translated to the OfIRAK protein of 464 amino acids. The deduced OfIRAK4 protein featured a bipartite domain structure composed of a death domain (DD) and a kinase domain (PKc). Teleost IRAK4 appears to be distinct and divergent from that of tetrapods in terms of its exon-intron structure and evolutionary relatedness. Analysis of the sequence upstream of translation initiation site revealed the presence of putative regulatory elements, including NF-κB-binding sites, which are possibly involved in transcriptional control of <italic>OfIRAK4</italic>. Quantitative real-time PCR (qPCR) was employed to assess the transcriptional expression of <italic>OfIRAK4</italic> in different juvenile tissues and post-injection of different immunogens and pathogens. Ubiquitous basal mRNA expression was widely detected with highest level in liver. <italic>In vivo</italic> flagellin (FLA) challenge significantly intensified its mRNA levels in intestine, liver and head kidney indicating its role in FLA-induced signaling. Meanwhile, up-regulated expression was also determined in liver and head kidney of animals challenged with potent immunogens (LPS and poly I:C) and pathogens (<italic>Edwardsiella tarda</italic> and <italic>Streptococcus iniae</italic> and rock bream iridovirus (RBIV)). Taken together, these data implicate that <italic>OfIRAK4</italic> might be engaged in antibacterial and antiviral immunity in rock bream.</p> </sec> </abstract>