Molecular characterization and functional analysis of duck TRAF6.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) plays a pivotal role in activating various signaling cascades as an intracellular signal transducer. Although significant progress has been made clarifying TRAF6 function in mammals, the role of TRAF6 in ducks (duTRAF6) remains poorly understood. In the present study, we cloned the full-length duTRAF6 cDNA from duck embryo fibroblasts (DEFs) for the first time. Real-time quantitative reverse transcription-polymerase chain reaction assays showed that duTRAF6 was widely expressed in different tissues. Overexpression of duTRAF6 activated nuclear factor kappa B (NF-κB) and induced interferon-β expression. Furthermore, a deletion mutant analysis revealed that the duTRAF6 region between aa 115 and 375 was essential for activating NF-κB. In addition, duTRAF6 knockdown by RNA interference significantly reduced poly(I:C)- and Sendai virus-induced NF-κB activation in DEFs. Taken together, our results demonstrate that duTRAF6 plays a crucial immunoregulatory role in the duck innate immune response.