Cutting edge: cells that carry A null allele for toll-like receptor 2 are capable of responding to endotoxin.
Cutting edge: cells that carry A null allele for toll-like receptor 2 are capable of responding to endotoxin.
复制标题
DOI：
10.4049/jimmunol.162.12.6971
复制
发表时间：
1999-06
影响因子：
4.4
通讯作者：
H. Heine;C. Kirschning;E. Lien;Brian G. Monks;M. Rothe;D. Golenbock
中科院分区：
文献类型：
--
作者：
H. Heine;C. Kirschning;E. Lien;Brian G. Monks;M. Rothe;D. Golenbock
Toll 样受体 (TLR) 2 和 TLR4 与细胞对 LPS（内毒素）的反应有关。 CD14 转染的中国仓鼠卵巢 (CHO)-K1 成纤维细胞 (CHO/CD14) 对内毒素极其敏感。与人类和小鼠 TLR2 相比，CHO-TLR2 的序列分析显示单个碱基对缺失。这种移码突变产生了一个替代的终止密码子，编码缺乏跨膜和细胞内结构域的蛋白质。 CHO-TLR2 cDNA 在瞬时转染人上皮肾 293 细胞后未能启用 LPS 信号传导。 CHO-TLR2 的定点诱变使得推测的全长仓鼠 TLR2 能够表达，从而在人上皮肾 293 细胞中赋予 LPS 反应性。来自原代仓鼠巨噬细胞的基因组 TLR2 DNA 也包含在 CHO 成纤维细胞中发现的移码突变。然而，仓鼠腹膜巨噬细胞被发现对脂多糖有正常反应，细胞因子的诱导证明了这一点。这些结果表明 TLR2 的表达对于哺乳动物对内毒素的反应来说是足够的，但不是必需的。
Toll-like receptor (TLR) 2 and TLR4 have been implicated in the responses of cells to LPS (endotoxin). CD14-transfected Chinese hamster ovary (CHO)-K1 fibroblasts (CHO/CD14) are exquisitely sensitive to endotoxin. Sequence analysis of CHO-TLR2, compared with human and mouse TLR2, revealed a single base pair deletion. This frameshift mutation resulted in an alternative stop codon, encoding a protein devoid of transmembrane and intracellular domains. CHO-TLR2 cDNA failed to enable LPS signaling upon transient transfection into human epithelial kidney 293 cells. Site-directed mutagenesis of CHO-TLR2 enabled expression of a presumed full-length hamster TLR2 that conferred LPS responsiveness in human epithelial kidney 293 cells. Genomic TLR2 DNA from primary hamster macrophages also contained the frameshift mutation found in CHO fibroblasts. Nevertheless, hamster peritoneal macrophages were found to respond normally to LPS, as evidenced by the induction of cytokines. These results imply that expression of TLR2 is sufficient but not essential for mammalian responses to endotoxin.