Establishment of a transient transfection system and expression of firefly luciferase in Entamoeba invadens

Entamoeba invadens is used as a model system to study trophozoite to cyst differentiation since Entamoeba histolytica, the causative agent of amoebiasis cannot encyst in culture. However, a system for introduction of cloned genes in E. invadens is not available. Here we report an electroporation-based method for transfection of E. invadens tophozoites and demonstrate the expression of firefly luciferase reporter gene driven from the E. invadens ribosomal protein L3 promoter. The efficiency of luciferase expression driven from the promoters of three different E. invadens genes (rpl3, rps10 and h2b) was tested and found to correlate with the in vivo expression levels of the respective gene. This system will permit the analysis of regulatory elements required for gene expression in E. invadens.