Hemmrich Georg, Miller David J, Bosch Thomas C G
Zoological Insitute, Christian-Albrechts-University Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.
Trends Immunol. 2007 Oct;28(10):449-54. doi: 10.1016/j.it.2007.08.003. Epub 2007 Sep 12.
Several of the key genes and pathways of vertebrate immunity appear to have much earlier origins than has been assumed previously and are present in some of the simplest of true animals. Surveys of recently released whole-genome sequences and large EST (expressed sequence tag) datasets imply that both the canonical Toll/Toll-like receptor (TLR) pathway and a prototypic complement-effector pathway, involving C3 and several membrane attack complex-perforin proteins, are present in corals and sea anemones, members of the basal phylum Cnidaria. However, both pathways are likely to have degenerated substantially in Hydra, leaving open the molecular mechanism by which antimicrobial activities are induced in this cnidarian. Surprisingly, the cnidarian genomes also encode a protein related to deuterostome RAG1 (recombination activation gene 1). The finding that RAG1 is likely to have originated from a Transib transposase implies that it might be possible to use in silico approaches to identify its target loci in 'lower' animals.
脊椎动物免疫的几个关键基因和途径的起源似乎比之前认为的要早得多，并且存在于一些最简单的真正动物中。对最近发布的全基因组序列和大型EST（表达序列标签）数据集的调查表明，经典的Toll/Toll样受体（TLR）途径和涉及C3及几种膜攻击复合物穿孔素蛋白的原型补体效应途径，都存在于珊瑚和海葵中，它们是基础刺胞动物门的成员。然而，这两种途径在水螅中可能已经大幅退化，这使得这种刺胞动物中诱导抗菌活性的分子机制尚不清楚。令人惊讶的是，刺胞动物基因组还编码一种与后口动物RAG1（重组激活基因1）相关的蛋白质。RAG1可能起源于Transib转座酶这一发现意味着，有可能使用计算机方法在“低等”动物中识别其靶位点。
