A 192 bp ERV fragment insertion in the first intron of porcine TLR6 may act as an enhancer associated with the increased expressions of TLR6 and TLR1

Abstract Background Toll-like receptors (TLRs) play important roles in building innate immune and inducing adaptive responses. Associations of the TLR genes polymorphisms with disease susceptibility, which are basis molecular breeding for resistant animals, have been reported extensively. Retrotransposon insertion (RIPs), as a new type markers developed recently, great potential population genetics quantitative trait locus mapping. In this study, bioinformatic prediction combined PCR-based amplification was employed to screen RIPs porcine genes. Their distribution examined, one RIP impact on gene activity phenotype further evaluated. Results Five RIPs, located at 3' flank TLR3 , 5' TLR5 intron 1 TLR6 TLR7 TLR8 respectively, were identified. These detected different breeds an uneven among them. By using dual luciferase assay 192 bp endogenous retrovirus (ERV) shown act enhancer increasing activities putative promoter two mini-promoters. Furthermore, real-time polymerase chain reaction (qPCR) analysis revealed significant association ( p < 0.05) ERV increased mRNA expression neighboring TLR1 downstream signaling pathway such MyD88 Myeloid differentiation factor 88 ) Rac1 (Rac family small GTPase 1) TIRAP (TIR domain containing adaptor protein) Tollip (Toll interacting well inflammatory factors IL6 (Interleukin 6) IL8 8), TNFα (Tumor necrosis alpha) tissues 30 day-old piglet. addition, serum concentrations also significantly upregulated by 0.05). Conclusions A total five identified loci. The first associated higher several cascade. Thus, may affecting regulation pathways, can be potentially applied animals.