Russo Roberta, Chiaramonte Marco, Matranga Valeria, Arizza Vincenzo
Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare "Alberto Monroy", Via U. La Malfa 153, 90146 Palermo, Italy.
Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche, Università degli Studi di Palermo, via Archirafi 20, Palermo, Italy.
Dev Comp Immunol. 2015 Aug;51(2):271-7. doi: 10.1016/j.dci.2015.04.007. Epub 2015 Apr 20.
The innate immune response involves proteins such as the membrane receptors of the Toll-like family (TLRs), which trigger different intracellular signalling pathways that are dependent on specific stimulating molecules. In sea urchins, TLR proteins are encoded by members of a large multigenic family composed of 60-250 genes in different species. Here, we report a newly identified mRNA sequence encoding a TLR protein (referred to as Pl-Tlr) isolated from Paracentrotus lividus immune cells. The partial protein sequence contained the conserved Toll/IL-1 receptor (TIR) domain, the transmembrane domain and part of the leucine repeats. Phylogenetic analysis of the Pl-Tlr protein was accomplished by comparing its sequence with those of TLRs from different classes of vertebrates and invertebrates. This analysis was suggestive of an evolutionary path that most likely represented the course of millions of years, starting from simple organisms and extending to humans. Challenge of the sea urchin immune system with poly-I:C, a chemical compound that mimics dsRNA, caused time-dependent Pl-Tlr mRNA up-regulation that was detected by QPCR. In contrast, bacterial LPS injury did not affect Pl-Tlr transcription. The study of the Tlr genes in the sea urchin model system may provide new perspectives on the role of Tlrs in the invertebrate immune response and clues concerning their evolution in a changing world.
天然免疫反应涉及多种蛋白质，如Toll样家族（TLRs）的膜受体，这些受体可触发不同的细胞内信号通路，这些信号通路依赖于特定的刺激分子。在海胆中，TLR蛋白由一个大型多基因家族的成员编码，不同物种中该家族由60 - 250个基因组成。在此，我们报告了一个新鉴定的mRNA序列，其编码从紫球海胆免疫细胞中分离出的一种TLR蛋白（称为Pl - Tlr）。部分蛋白质序列包含保守的Toll/IL - 1受体（TIR）结构域、跨膜结构域和部分亮氨酸重复序列。通过将Pl - Tlr蛋白的序列与来自不同类别的脊椎动物和无脊椎动物的TLR序列进行比较，完成了对Pl - Tlr蛋白的系统发育分析。该分析表明了一条进化路径，这条路径很可能代表了数百万年的历程，从简单生物开始并延伸至人类。用聚肌胞苷酸（poly - I:C，一种模拟双链RNA的化合物）刺激海胆免疫系统，导致了通过定量PCR检测到的时间依赖性Pl - Tlr mRNA上调。相比之下，细菌脂多糖损伤并未影响Pl - Tlr的转录。在海胆模型系统中对Tlr基因的研究可能为Tlr在无脊椎动物免疫反应中的作用提供新的视角，并为它们在不断变化的世界中的进化提供线索。
