Identification and characterization a novel polar tube protein (NbPTP6) from the microsporidian Nosema bombycis

Parasites & Vectors

Guoqing Pan¹  Keke Liu¹  Mengxian Long¹  Youpeng Fan¹  Jie Chen¹  Lijun Wang¹  Bingqian Zhou¹  Xianzhi Meng¹  Qing Lv¹  Zeyang Zhou² 

[1] State Key Laboratory of Silkworm Genome Biology, Southwest University, 400715, Chongqing, China;Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, 400715, Chongqing, China;State Key Laboratory of Silkworm Genome Biology, Southwest University, 400715, Chongqing, China;Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, 400715, Chongqing, China;College of Life Sciences, Chongqing Normal University, 400047, Chongqing, China;

关键词: Nosema bombycis;    Novel;    Polar tube protein;    Localization;    Cell-binding ability;   

DOI  :  10.1186/s13071-020-04348-z

来源: Springer

【 摘 要 】

BackgroundMicrosporidians are opportunistic pathogens with a wide range of hosts, including invertebrates, vertebrates and even humans. Microsporidians possess a highly specialized invasion structure, the polar tube. When spores encounter an appropriate environmental stimulation, the polar tube rapidly everts out of the spore, forming a 50–500 µm hollow tube that serves as a conduit for sporoplasm passage into host cells. The polar tube is mainly composed of polar tube proteins (PTPs). So far, five major polar tube proteins have been isolated from microsporidians. Nosema bombycis, the first identified microsporidian, infects the economically important insect silkworm and causes heavy financial loss to the sericulture industry annually.ResultsA novel polar tube protein of N. bombycis (NbPTP6) was identified. NbPTP6 was rich in histidine (H) and serine (S), which contained a signal peptide of 16 amino acids at the N-terminus. NbPTP6 also had 6 potential O-glycosylation sites and 1 potential N-glycosylation site. The sequence alignment analysis revealed that NbPTP6 was homologous with uncharacterized proteins from other microsporidians (Encephalitozoon cuniculi, E. hellem and N. ceranae). Additionally, the NbPTP6 gene was expressed in mature N. bombycis spores. Indirect immunofluorescence analysis (IFA) result showed that NbPTP6 is localized on the whole polar tube of the germinated spores. Moreover, IFA, enzyme-linked immunosorbent (ELISA) and fluorescence-activated cell sorting (FACS) assays results revealed that NbPTP6 had cell-binding ability.ConclusionsBased on our results, we have confirmed that NbPTP6 is a novel microsporidian polar tube protein. This protein could adhere with the host cell surface, so we speculated it might play an important role in the process of microsporidian infection.

【 授权许可】

CC BY