Department of Biology, Indiana University, Bloomington, IN, USA.
Department of Biology, Indiana University, Bloomington, IN, USA.
Trends Microbiol. 2022 Feb;30(2):185-198. doi: 10.1016/j.tim.2021.06.008. Epub 2021 Jul 9.
Bacterial endosymbionts induce dramatic phenotypes in their arthropod hosts, including cytoplasmic incompatibility, feminization, parthenogenesis, male killing, parasitoid defense, and pathogen blocking. The molecular mechanisms underlying these effects remain largely unknown but recent evidence suggests that protein toxins secreted by the endosymbionts play a role. Here, we describe the diversity and function of endosymbiont proteins with homology to known bacterial toxins. We focus on maternally transmitted endosymbionts belonging to the Wolbachia, Rickettsia, Arsenophonus, Hamiltonella, Spiroplasma, and Cardinium genera because of their ability to induce the above phenotypes. We identify at least 16 distinct toxin families with diverse enzymatic activities, including AMPylases, nucleases, proteases, and glycosyltransferases. Notably, several annotated toxins contain domains with homology to eukaryotic proteins, suggesting that arthropod endosymbionts mimic host biochemistry to manipulate host physiology, similar to bacterial pathogens.
细菌内共生体在其节肢动物宿主中诱导出显著的表型，包括细胞质不亲和、雌性化、孤雌生殖、雄性致死、寄生蜂防御和病原体阻断。这些效应的分子机制在很大程度上仍然未知，但最近的证据表明，内共生体分泌的蛋白毒素发挥了作用。在这里，我们描述了与已知细菌毒素具有同源性的共生体蛋白的多样性和功能。我们专注于能够诱导上述表型的母系传递的共生体，属于沃尔巴克氏体、立克次氏体、放线菌、汉森氏菌、螺原体和卡他莫拉菌属。我们确定了至少 16 种不同的毒素家族，具有多种酶活性，包括 AMP 酶、核酸酶、蛋白酶和糖基转移酶。值得注意的是，几个注释的毒素含有与真核蛋白同源的结构域，这表明节肢动物内共生体模拟宿主生物化学来操纵宿主生理学，类似于细菌病原体。
