IκB kinase β (IKKβ), a catalytic subunit of the IKK complex, is involved in a wide array of biological processes, particularly in inflammation and innate immunity. Although extensive studies have been carried out to explore the roles of mammalian IKKβs in innate immune response, the function of IKKβ in avian innate immunity is largely unknown. Here, we cloned and characterized the duck IKKβ (duIKKβ) gene for the first time. DuIKKβ encoded 755 amino acids and displayed high sequence similarity to pseudopodoces and haliaeetus IKKβs. DuIKKβ transcripts were widely distributed in all tested tissues, especially with high expression in the thymus and bursa of Fabricius. Overexpression of duIKKβ promoted NF-κB activation and initiated the downstream cytokines expression including IFN-β, ZAP, PKR, IL-8, and CCL5 in duck embryo fibroblasts. Furthermore, knockdown of endogenous duIKKβ significantly reduced LPS-, poly(I:C)- or SeV-induced NF-κB activation. Finally, we demonstrated that duIKKβ showed antiviral activity against Duck Tembusu virus infection. Our findings provide insights into the roles of duIKKβ in avian innate immunity.

IκB 激酶 β (IKKβ) 是 IKK 复合物的催化亚基，参与广泛的生物过程，特别是炎症和先天免疫。尽管已经进行了广泛的研究来探索哺乳动物 IKKβ 在先天免疫反应中的作用，但 IKKβ 在禽类先天免疫中的功能在很大程度上是未知的。在这里，我们首次克隆并鉴定了鸭 IKKβ (duIKKβ) 基因。DuIKKβ 编码 755 个氨基酸，并显示出与伪足纲和海藻 IKKβ 的高度序列相似性。DuIKKβ 转录物广泛分布于所有测试组织中，特别是在法氏胸腺和法氏囊中高表达。duIKKβ 的过表达促进了 NF-κB 的活化，并启动了鸭胚胎成纤维细胞中下游细胞因子的表达，包括 IFN-β、ZAP、PKR、IL-8 和 CCL5。此外，内源性 duIKKβ 的敲低显着降低了 LPS-、聚 (I:C)- 或 SeV 诱导的 NF-κB 活化。最后，我们证明了 duIKKβ 对 Duck Tembusu 病毒感染具有抗病毒活性。我们的研究结果提供了对 duIKKβ 在禽类先天免疫中的作用的见解。