Identification of Toll-like Receptor （TLR） 4 Gene in Wild Boar

Toll-like receptor （TLR） 4 plays an important role in the innate immune system and has been involved in resistance/ susceptibility to a number of diseases as revealed by studies in human and other domestic animals. Wild boar survives in natural environment without artificial interference and may be different from domestic pig in innate immune system. Here, the complete coding sequence of TLR4 and TLR4A was cloned in wild boar, and two other alternative splicing variants, TLR4B and TLR4C, were obtained. Compared to the counterpart from domestic pig （GcnBank No. AJ628065）, there were five SNPs, c.510T〉C, c.960A〉G, c.962A〉G, c.1605T〉G and c.1824A〉G, in the coding sequence of wild boar TLR4A gene. TLR4 gene was expressed in all the tissues from wild boar studied with the most abundance in spleen tissue, and mRNA level was significantly lower in spleen from wild boar than that from Min pig. The allele distribution was significantly different at polymorphic loci c.962G〉A and c.1027C〉A （p〈0.01） between wild boar and Min pig. The results would contribute to understand the innate immune system in wild boar.