Efficient genome engineering of Toxoplasma gondii using the TALEN technique

Abstract

Background: Aromatic amino acid hydroxylase 2 (AAH2) is a bradyzoite-specific upregulated protein that may alter host behaviour by altering the host dopaminergic pathway. To better understand the role of the parasite's AAH2 in host-parasite interactions, we generated an AAH2 fluorescent marker strain of T. gondii using the TALEN technique. Methods: We generated an AAH2 fluorescent marker strain of T. gondii, which was designated PRU/AAH2-eGFP, using the TALEN technique. This strain stably expressed pyrimethamine resistance for screening and expressed enhanced green fluorescent protein (eGFP)-tagged AAH2 in the bradyzoite stage. The bradyzoite conversion of PRU/AAH2-eGFP was observed both in vitro and in vivo. The fluorescence localization of AAH2 in mouse models of chronic infection was observed by a Bruker in vivo imaging system. Results: Transgenic T. gondii was successfully generated by the TALEN system. The eGFP-tagged AAH2 could be detected by in vivo imaging. Conclusions: This study verified the feasibility of using TALEN technology for T. gondii research and provided an in vivo imaging method for in vivo research of bradyzoite-stage proteins.