Evolutionary and functional studies on microsporidian ATP-binding cassettes: Insights into the adaptation of microsporidia to obligated intracellular parasitism
Evolutionary and functional studies on microsporidian ATP-binding cassettes: Insights into the adaptation of microsporidia to obligated intracellular parasitism
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小孢子虫 ATP 结合盒的进化和功能研究：深入了解小孢子虫对细胞内寄生的适应
DOI：
10.1016/j.meegid.2018.12.022
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发表时间：
2019-03-01
影响因子：
3.2
通讯作者：
Li, Tian
中科院分区：
文献类型：
--
作者：
He, Qiang;Vossbrinck, Charles R.;Li, Tian
ATP结合盒（ABC）转运蛋白是最大的跨膜蛋白家族，存在于所有生命领域。ABC转运蛋白参与多种生物过程，并且作为外排蛋白在多药耐药性中起重要作用。然而，在微孢子虫中尚未对ABC转运蛋白进行研究，微孢子虫是一大类专性细胞内寄生虫，可感染几乎所有动物，包括人类。在此，从18个微孢子虫基因组中总共鉴定出234种ABC转运蛋白，并将其分为5个亚家族，包括74个ABCB、2个ABCC、18个ABCE、15个ABCF、102个ABCG以及23个未分类成员。大多数生物中存在的两个亚家族ABCA和ABCD在微孢子虫中缺失。系统发育分析表明，微孢子虫的ABCB和ABCG亚家族通过近期的基因重复而扩增，这导致它们成为微孢子虫中两个最大的亚家族。通过实时定量聚合酶链反应（qRT - PCR）和蛋白质印迹（Western blotting）进行的功能分析显示，家蚕微孢子虫（Nosema bombycis）的一个ABCG成员NoboABCG1.1在成熟孢子中表达，并且在感染家蚕中肠后从感染第1天到第6天表达上调。免疫荧光分析（IFA）和免疫电镜分析（IEM）表明，NoboABCG1.1定位于孢原质、裂殖体和成熟孢子的质膜上。在NoboABCG1.1表达被RNA干扰后，家蚕微孢子虫的繁殖受到显著抑制，这表明NoboABCG1.1对病原体增殖很重要。总之，我们的研究揭示了ABC转运蛋白在微孢子虫适应细胞内寄生过程中发生了进化，并在病原体发育中起重要作用。
ATP-binding cassette (ABC) transporters comprise the largest family of transmembrane proteins and are found in all domains of life. The ABCs are involved in a variety of biological processes and as exporters play important roles in multidrug resistance. However, the ABC transporters have not been addressed in microsporidia, which are a very large group of obligate intracellular parasites that can infect nearly all animals, including humans. Here, a total of 234 ABC transporters were identified from 18 microsporidian genomes and classified into five subfamilies, including 74 ABCBs, 2 ABCCs, 18 ABCEs, 15 ABCFs, 102 ABCGs and 23 uncategorized members. Two subfamilies, ABCA and ABCD, are found in most organisms, but lost in microsporidia. Phylogenetic analysis indicated that microsporidian ABCB and ABCG subfamilies expanded by recent gene duplications, which resulted in the two largest subfamilies in microsporidia. Functional analysis via qRT-PCR and Western blotting revealed that NoboABCG1.1, an ABCG member of Nosema bombycis, is expressed in mature spores and upregulated from 1 dpi to 6 dpi in infected silkworm midgut. IFA and IEM analysis showed that NoboABCG1.1 is localized on the plasma membrane of the sporoplasm, meront and mature spore. The propagation of N. bombycis was significantly inhibited after the RNAi of NoboABCG1.1 expression, indicating that NoboABCG1.1 is important to the pathogen proliferation. In conclusion, our study uncovered that the ABCs evolved during microsporidia adaption to intracellular parasitism and play important roles in the pathogen development.