Differential Expression of Three Species-Specific MEDLE Proteins.

and share highly similar proteomes, with merely ~3% divergence in overall nucleotide sequences. -specific MEDLE family is one of the major differences in gene content between the two species. Comparative genomic analysis indicated that MEDLE family may contribute to differences in host range among spp. Previous studies have suggested that CpMEDLE-1 encoded by and CpMEDLE-2 encoded by are potentially involved in the invasion of . In this study, we expressed in the -specific member of the MEDLE protein family, ChMEDLE-1 encoded by and two -specific members, CpMEDLE-3 encoded by and CpMEDLE-5 encoded by . Quantitative PCR, immunofluorescence staining and neutralization assay were conducted to assess their biologic characteristics. The expression of the gene was high during 12-48 h of the culture, while the expression of was the highest at 2 h. ChMEDLE-1 and CpMEDLE-3 proteins were mostly located in the anterior and mid-anterior region of sporozoites and merozoites, whereas CpMEDLE-5 was expressed over the entire surface of these invasive stages. Polyclonal antibodies against MEDLE proteins had different neutralization efficiency, reaching approximately 50% for ChMEDLE-1 and 60% for CpMEDLE-3, but only 20% for CpMEDLE-5. The differences in protein and gene expression and neutralizing capacity indicated the MEDLE proteins may have different roles during invasion and growth.