Wang Ying, Dang Xiaoqun, Ma Qiang, Liu Fangyan, Pan Guoqing, Li Tian, Zhou Zeyang
State Key Laboratory of Silkworm genome Biology,Southwest University,Chongqing 400716,China.
Parasitology. 2015 Apr;142(4):534-42. doi: 10.1017/S0031182014001565. Epub 2014 Nov 3.
Nosema bombycis, a pathogen of silkworm pebrine, is an obligate unicellular eukaryotic parasite. It is reported that the spore wall proteins have essential functions in the adherence and infection process of microsporidia. To date, the information related to spore wall proteins from microsporidia is still limited. Here, a 44 kDa spore wall protein NbSWP16 was characterized in N. bombycis. In NbSWP16, a 25 amino acids signal peptide and 3 heparin binding motifs were predicted. Interestingly, a region that contains 3 proline-rich tandem repeats lacking homology to any known protein was also present in this protein. The immunofluorescence analysis (IFA) demonstrated that distinct fluorescent signals were detected both on the surface of mature spores and the germinated spore coats. Immunolocation by electron microscopy revealed that NbSWP16 localized on the exospore regions. Finally, spore adherence analysis indicated that spore adherence to host cell was decreased more than 20% by anti-NbSWP16 blocking compared with the negative control in vitro. In contrast with anti-NbSWP16, no remarkable decrement inhibition was detected when antibodies of NbSWP16 and NbSWP5 were used simultaneously. Collectively, these results suggest that NbSWP16 is a new exospore protein and probably be involved in spore adherence of N. bombycis.
家蚕微孢子虫是家蚕微粒子病的病原体，是一种专性单细胞真核寄生虫。据报道，孢子壁蛋白在微孢子虫的黏附与感染过程中发挥着重要作用。迄今为止，关于微孢子虫孢子壁蛋白的信息仍然有限。在此，对家蚕微孢子虫中的一种44 kDa孢子壁蛋白NbSWP16进行了表征。在NbSWP16中，预测有一个25个氨基酸的信号肽和3个肝素结合基序。有趣的是，该蛋白中还存在一个区域，包含3个富含脯氨酸的串联重复序列，与任何已知蛋白均无同源性。免疫荧光分析（IFA）表明，在成熟孢子表面和萌发的孢子壁上均检测到明显的荧光信号。电子显微镜免疫定位显示NbSWP16定位于外孢子区域。最后，孢子黏附分析表明，与体外阴性对照相比，抗NbSWP16阻断使孢子对宿主细胞的黏附减少了20%以上。与抗NbSWP16相反，当同时使用NbSWP16和NbSWP5的抗体时，未检测到明显的抑制作用。总体而言，这些结果表明NbSWP16是一种新的外孢子蛋白，可能参与家蚕微孢子虫的孢子黏附过程。
