Wu Yuyuan, Liang Haiying, Wang Zhixin, Lei Qiannan, Xia Liqun
Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China.
Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China.
Comp Biochem Physiol B Biochem Mol Biol. 2017 Dec;214:19-26. doi: 10.1016/j.cbpb.2017.08.006. Epub 2017 Sep 8.
Graft rejection due to immune incompatibility is a common occurrence in pearl culture, which often cause death to the host oyster. To improve cultured pearl production, host mortality and bead rejection rates must be reduced. Toll-like receptor 4 (TLR4) plays an important role in innate immunity, and may be related to allograft rejection. Here, we cloned the TLR4 cDNA from the pearl oyster Pinctada fucata martensii (PmTLR4). PmTLR4 cDNA was 3138bp, including a 2625bp open reading frame encoding 874 amino acids. The predicted PmTLR4 protein was structurally typical of the TLR family. PmTLR4 had relatively high sequence similarity and identity to the TLR4 of the Cyclina sinensis (48.1% and 27.6%, respectively). Multiple alignment of TLR4 sequences across species indicated that the Toll/interleukin-1 (IL-1) receptor domain was conserved among species. PmTLR4 mRNA was expressed in all tissues tested, with the most abundant mRNA expression in hepatopancreas and gill in P. fucata martensii. After being stressed by either lipopolysaccharide (LPS) exposure or the nucleus insertion operation, PmTLR4 mRNA expression increased significantly in the hemocytes as compared to controls. Peak level of PmTLR4 mRNA was observed 6h after the LPS injection, and 2d after the nucleus insertion operation. These data suggest that PmTLR4 may play a vital role in the induction of innate immunity and is therefore associated with allograft immunity in the pearl oyster P. fucata martensii.
由于免疫不相容导致的移植物排斥在珍珠养殖中很常见，这常常导致宿主牡蛎死亡。为了提高养殖珍珠的产量，必须降低宿主死亡率和珠核排斥率。Toll样受体4（TLR4）在先天免疫中起重要作用，可能与同种异体移植排斥有关。在此，我们从马氏珠母贝（PmTLR4）中克隆了TLR4 cDNA。PmTLR4 cDNA为3138bp，包括一个2625bp的开放阅读框，编码874个氨基酸。预测的PmTLR4蛋白在结构上是TLR家族的典型代表。PmTLR4与中华圆田螺的TLR4具有相对较高的序列相似性和同一性（分别为48.1%和27.6%）。跨物种的TLR4序列多重比对表明，Toll/白细胞介素-1（IL-1）受体结构域在物种间是保守的。PmTLR4 mRNA在所有测试组织中均有表达，在马氏珠母贝的肝胰腺和鳃中mRNA表达最为丰富。在受到脂多糖（LPS）暴露或核植入操作应激后，与对照组相比，血细胞中PmTLR4 mRNA表达显著增加。在注射LPS后6小时和核植入操作后2天观察到PmTLR4 mRNA的峰值水平。这些数据表明，PmTLR4可能在先天免疫诱导中起关键作用，因此与马氏珠母贝的同种异体移植免疫相关。
