Molecular cloning of rock bream’s (Oplegnathus fasciatus) tumor necrosis factor receptor-associated factor 2 and its role in NF-κB activiation

Tumor necrosis factor receptor-associated factor 2 (TRAF2) acts as a transducer of tumor necrosis factor-α (TNF-α)-triggered cell signals which results in inflammation, cell proliferation and antiapoptotic response. In this study, we have cloned cDNA of rock bream (Oplegnathus fasciatus) TRAF2, and analyzed its function in activation of NF-κB. The full length cDNA of rock bream TRAF2 consisted of 95 bp 5′ UTR, 335 bp 3′ UTR, and 1563 bp ORF encoding 520 amino acids that contained N-terminal RING-type and TRAF-type zinc finger domains and a C-terminal TRAF domain. The deduced amino acid sequence of rock bream TRAF2 showed more than 75% identity with other fish TRAF2s, and even as high as 56% identity with mouse and human TRAF2 proteins. To know whether the rock bream TRAF2 involves in NF-κB activation, Epithelioma papulosum cyprini (EPC) cells harboring an NF-κB reporting vector were transfected with a vector expressing rock bream TRAF2 or a control empty vector. NF-κB activity of EPC cells was significantly increased by exposure to the rock bream recombinant TNF-α. EPC cells transfected with the vector expressing rock bream TRAF2 showed significantly higher NF-κB activity by stimulation with the recombinant TNF-α than cells transfected with a control empty vector, suggesting the present rock bream TRAF2 acts as a transducer of TNF-α-mediated cell signals that enhance NF-κB activation.