Luallen Robert J, Reinke Aaron W, Tong Linda, Botts Michael R, Félix Marie-Anne, Troemel Emily R
Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego (UCSD), La Jolla, California, United States of America.
École Normale Supérieure, Institut de Biologie de l'ENS (IBENS), CNRS-INSERM, Paris, France.
PLoS Pathog. 2016 Jun 30;12(6):e1005724. doi: 10.1371/journal.ppat.1005724. eCollection 2016 Jun.
Microbial pathogens often establish infection within particular niches of their host for replication. Determining how infection occurs preferentially in specific host tissues is a key aspect of understanding host-microbe interactions. Here, we describe the discovery of a natural microsporidian parasite of the nematode Caenorhabditis elegans that displays a unique tissue tropism compared to previously described parasites of this host. We characterize the life cycle of this new species, Nematocida displodere, including pathogen entry, intracellular replication, and exit. N. displodere can invade multiple host tissues, including the epidermis, muscle, neurons, and intestine of C. elegans. Despite robust invasion of the intestine very little replication occurs there, with the majority of replication occurring in the muscle and epidermis. This feature distinguishes N. displodere from two closely related microsporidian pathogens, N. parisii and N. sp. 1, which exclusively invade and replicate in the intestine. Comparison of the N. displodere genome with N. parisii and N. sp. 1 reveals that N. displodere is the earliest diverging species of the Nematocida genus. Over 10% of the proteins encoded by the N. displodere genome belong to a single species-specific family of RING-domain containing proteins of unknown function that may be mediating interactions with the host. Altogether, this system provides a powerful whole-animal model to investigate factors responsible for pathogen growth in different tissue niches.
微生物病原体通常在其宿主的特定生态位内建立感染以进行复制。确定感染如何优先在特定宿主组织中发生是理解宿主 - 微生物相互作用的一个关键方面。在这里，我们描述了一种秀丽隐杆线虫的天然微孢子虫寄生虫的发现，与该宿主先前描述的寄生虫相比，它表现出独特的组织嗜性。我们对这种新物种——破坏线虫微孢子虫（Nematocida displodere）的生命周期进行了表征，包括病原体进入、细胞内复制和退出。破坏线虫微孢子虫可以侵入多种宿主组织，包括秀丽隐杆线虫的表皮、肌肉、神经元和肠道。尽管它能大量侵入肠道，但在那里很少发生复制，大部分复制发生在肌肉和表皮中。这一特征将破坏线虫微孢子虫与两种密切相关的微孢子虫病原体——巴氏线虫微孢子虫（N. parisii）和线虫微孢子虫1号（N. sp. 1）区分开来，后两者仅侵入肠道并在其中复制。将破坏线虫微孢子虫的基因组与巴氏线虫微孢子虫和线虫微孢子虫1号的基因组进行比较，发现破坏线虫微孢子虫是线虫微孢子虫属中分化最早的物种。破坏线虫微孢子虫基因组编码的蛋白质中超过10%属于一个单一的物种特异性家族，该家族含有功能未知的含RING结构域的蛋白质，可能介导与宿主的相互作用。总之，这个系统提供了一个强大的全动物模型，用于研究不同组织生态位中病原体生长的相关因素。
