Molecular Cloning and Structural Characterization of the Porcine TLR4 Ectodomain

類鐸受體4外膜區域之分子選殖及蛋白質結構預測

蔡信雄(Shinn-Shyong Tsai) ； 游景盛(Chin-Sheng Yu) ； 鍾文彬(Wen-Bin Chung) ； 白惠珠(Hui-Chu Pai) ； 劉侑霖(Yu-Lin Liu) ； 劉宏仁(Hung-Jen Liu) ； 林茂勇(Maw-Yeong Lin) ； 謝耀清(Yao-Ching Hsieh) ； 鄭力廷(Li-Ting Cheng) ； 莊國賓(Kuo-Pin Chuang)

《臺灣獸醫學雜誌》 36卷4期 (2010/12) Pp. 279-287

https://doi.org/10.7009/TVJ.201012.0279

摘要

類鐸受體4(TLR-4)在豬隻之先天性及後天性免疫反應佔有極重要之角色。因此本研究分析15隻台灣豬隻之TLR-4細胞膜外部位基因並表現其蛋白質，依據基因及蛋白質分析結果，共發現有五個核酸變異點(A961G, A963G, A1027C, T1606G, A1824G)而這樣基因的變異會進一步造成三個胺基酸變異(H321R, K343Q, F535L)。本篇是第一篇發現兩個位在TLR-4之leucine-rich repeat胺基酸變異熱點H321R和K343Q會出現於同一隻台灣豬中之報導，另外藉由三D立體結構模擬，發現這三個胺基酸變異點會對TLR-4之結構產生改變，且這樣的改變會影響TLR-4和MD2之間的結合。希望藉由TLR-4基因之多型性及蛋白質功能研究能對將來豬隻育種、營養及疫苗的發展能有所助益。

關鍵字

豬隻 ； 類鐸受體4 ； 膜外區域 ； 分子選殖

並列摘要

Toll-like receptor 4 (TLR4) regulates innate and adaptive immune responses in pigs. However, the porcine TLR4 gene and structure have not been well-characterized. The ectodomain of porcine TLR4 (pTLR4-ECD) was cloned from a pool of 15 pigs in Taiwan and analyzed. Based on genetic and protein analyses, 5 nucleotide substitutions (A961G, A963G, A1027C, T1606G, A1824G) and three amino acid substitutions (H321 R, K343Q, F535L) were noted. This is the first report documenting the appearance of the hot spot substitutions H321R and K343Q, which are found in the leucine-rich repeat (LRR) of pTLR4. According to three-dimensional modeling, the pTLR4-ECD structure is altered by these amino acid substitutions. These mutations may disturb the binding affinity between pTLR4 and its structural partner MD2. An understanding of the correlation between pTLR4 polymorphisms and immune responses will be important for selecting breeds and developing vaccines in the pork industry.

並列關鍵字

ectodomain ； molecular cloning ； porcine ； TLR4