Xu Jinzhi, Luo Jian, Chen Jiajing, Vossbrinck Charles R, Li Tian, Zhou Zeyang
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing 400715, China.
J Fungi (Basel). 2022 May 24;8(6):551. doi: 10.3390/jof8060551.
Microsporidia are a group of obligate intracellular pathogens infecting nearly all animal phyla. The microsporidian has been isolated from several lepidopteran species, including the economy-important silkworms as well as several crop pests. Proteins secreted by parasites can be important virulent factors in modulating host pathways. Ricin is a two-chain lectin best known for its extreme vertebrate toxicity. Ricin B lectin-like proteins are widely distributed in microsporidia, especially in In this study, we identify 52 Ricin B lectin-like proteins (RBLs) in . We show that the RBLs (NbRBLs) are classified into four subfamilies. The subfamily 1 was the most conserved, with all members having a Ricin B lectin domain and most members containing a signal peptide. The other three subfamilies were less conserved, and even lost the Ricin B lectin domain, suggesting that NbRBLs might be a multi-functional family. Our study here indicated that the NbRBL family had evolved by producing tandem duplications firstly and then expanded by segmental duplications, resulting in concentrated localizations mainly in three genomic regions. Moreover, based on RNA-seq data, we found that several s were highly expressed during infection. Further, the results show that the NbRBL28 was secreted into host nucleus, where it promotes the expressions of genes involved in cell cycle progression. In summary, the great copy number, high divergence, and concentrated genome distribution of the NbRBLs demonstrated that these proteins might be adaptively evolved and played a vital role in the multi-host .
微孢子虫是一类专性细胞内病原体，感染几乎所有动物门类。已从多种鳞翅目昆虫中分离出微孢子虫，包括具有重要经济价值的家蚕以及几种农作物害虫。寄生虫分泌的蛋白质可能是调节宿主通路的重要致病因子。蓖麻毒素是一种双链凝集素，以其对脊椎动物的极高毒性而闻名。蓖麻毒素B凝集素样蛋白广泛分布于微孢子虫中，尤其是在本研究中，我们在中鉴定出52种蓖麻毒素B凝集素样蛋白（RBLs）。我们发现这些RBLs（NbRBLs）分为四个亚家族。亚家族1最为保守，所有成员都有一个蓖麻毒素B凝集素结构域，且大多数成员含有信号肽。其他三个亚家族保守性较低，甚至失去了蓖麻毒素B凝集素结构域，这表明NbRBLs可能是一个多功能家族。我们的研究表明，NbRBL家族首先通过串联重复进化，然后通过片段重复扩展，导致主要集中定位在三个基因组区域。此外，基于RNA测序数据，我们发现几种在感染期间高度表达。进一步的结果表明，NbRBL28分泌到宿主细胞核中，在那里它促进参与细胞周期进程的基因的表达。总之，NbRBLs的大量拷贝数、高度分化和集中的基因组分布表明这些蛋白质可能是适应性进化的，并且在多宿主中起着至关重要的作用。
