Toxoplasma gondii: Identification and characterization of bradyzoite-specific deoxyribose phosphate aldolase-like gene (TgDPA).

Toxoplasma gondii undergoes stage conversion from tachyzoites to bradyzoites in intermediate hosts. There have been many reports on bradyzoite-specific genes which are thought to be involved in stage conversion. Here, we described a novel T. gondii deoxyribose phosphate aldolase-like gene (TgDPA) expressing predominantly in bradyzoites. The TgDPA gene encodes 286 amino acids having a predicted molecular weight of 31kDa. Sequence analysis revealed that TgDPA had a deoxyribose phosphate aldolase (DeoC) domain with about 30% homology with its Escherichia coli counterpart. RT- and quantitative PCR analyses showed that the TgDPA gene was more expressed in bradyzoites and that its expression gradually increased during in vitro tachyzoite-to-bradyzoite stage conversion. A polyclonal antibody against recombinant TgDPA protein was raised in rabbits, and immunofluorescent analysis demonstrated that TgDPA was expressed in bradyzoites in vivo and in vitro. These findings indicate that the TgDPA gene is a new bradyzoite-specific marker and might play a role in bradyzoites.