Expression and characterization of a novel spore wall protein from Nosema bombycis

Microsporidia are obligate intracellular, eukaryotic, spore-forming parasites. The environmentally resistant spores, which harbor a rigid cell wall, are critical for their survival outside their host cells and host-to-host transmission. The spore wall comprises two major layers: the exospore and the endospore. In Nosema bombycis , five spore wall proteins have been identified which contain two endosporal proteins (SWP25 and SWP30) and three exosporal proteins ( Nb SWP5, SWP26 and SWP32). In the current study, we identied a novel endosporal protein Nb SWP12 with calculated molecular mass of 25.56 kDa and pI of 6.69 using SDS-PAGE and MALDI-TOF MS technique. Followed by gene cloning and protein expression, polyclonal antibody production, indirect immunouorescence antibody test, and immunoelectron microscopy analysis, the results indicate that this protein is localized to the endospore and has no obvious enhancement on adherence to host cells. The characterization of this novel spore wall protein from N. bombycis may facilitate our further investigation of the relationship between N. bombycis and its host, Bombyx mori . Keywords: Microsporidia, Nosema bombycis , Spore wall protein, Nb SWP12 African Journal of Biotechnology , Vol 13(24) 2459-2465