Identification, localization, and bioinformatics analysis of the novel EhSWP12 in Ecytonucleospora hepatopenaei

Ecytonucleospora hepatopenaei (EHP) is an obligate intracellular microsporidian that causes severe disease in Litopenaeus vannamei but whose infection mechanism remains elusive. Because the spore wall is a critical interface between the parasite and its environment, characterizing the functionally unstudied protein SWP12 is essential for elucidating host - microsporidian interactions. In this study, we cloned the full-length open reading frame (ORF) of EHP SWP12, designated EhSWP12, which is 735 bp in length and encodes a 244-amino-acid polypeptide. Bioinformatic analyses revealed that EhSWP12 contains no signal peptide or transmembrane domain but possesses an AH/BAR domain, with a predicted isoelectric point (pI) of 9.05 and a molecular mass (Mw) of 28.7 kDa. The EhSWP12 gene was subsequently expressed in Escherichia coli, and indirect immunofluorescence assays (IFA) demonstrated that the protein localizes to the mature spore wall. Further subcellular localization studies identified its presence in both the exospore and endospore layers. Our findings indicate that EhSWP12 is a membrane-associated protein, suggesting that it plays a pivotal role in the EHP life cycle. These results enhance our understanding of EHP biology and provide a theoretical and technical foundation for the future investigation of its proliferation and infection mechanisms.