title: TgERK7 is involved in the intracellular proliferation of Toxoplasma gondii.
abstract: Toxoplasma gondii uses a unique mechanism to fulfill its asexual life cycles by which the parasite can infect all the warm-blooded animals including humans. Mitogen-activated protein kinase (MAPK) or extracellular signal-regulated kinase (ERK) pathway widely existed in eukaryotic cells mediates the conversion of environmental stimuli to intracellular events such as proliferation and differentiation. Their counterparts have been identified in Apicomplexan parasites such as ERK7 in T. gondii. To confirm whether the unique mechanism of T. gondii is relevant to MAPK/ERK member, we created a mutant (ΔTgERK7) in GT1 tachyzoites using double homologous recombination method. Our results of virulence evaluation showed 100 % survival of all the ΔTgERK7-infected mice until 35 days post-challenge compared to no survival in wild-type GT1-infected group (10.6 ± 0.34 days). Furthermore, lower parasite loads were detected in the peritoneal fluid of ΔTgERK7-infected mice (P < 0.05). To ensure whether or not ERK7 gene knockout leads to the growth deficiency of T. gondii, the intracellular proliferation of ΔTgERK7 was also examined in vitro. Our data indicated that the proliferation of ΔTgERK7 parasites was significantly prolonged in comparison with wild-type GT1 tachyzoites (P < 0.05). Therefore, we concluded that TgERK7 is important for the intracellular proliferation of T. gondii, which further emphasized that MAPK/ERK derived from T. gondii participates in the regulation of the asexual life cycles to ensure the survival and reinfections of this parasite.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China.|Military Veterinary Institute, Academy of Military Medical Sciences, Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun, Jilin Province, 130122, People's Republic of China.|College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province, 163319, People's Republic of China.
authors.forename: Zhong-Yuan
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Military Veterinary Institute, Academy of Military Medical Sciences, Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun, Jilin Province, 130122, People's Republic of China.
authors.forename: Ze-Dong
authors.initials: ZD
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China.
authors.forename: Si-Yang
authors.initials: SY
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China. xingquanzhu1@hotmail.com.|College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province, 163319, People's Republic of China. xingquanzhu1@hotmail.com.
authors.forename: Xing-Quan
authors.initials: XQ
authors.lastname: Zhu
authors.affiliation: Military Veterinary Institute, Academy of Military Medical Sciences, Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun, Jilin Province, 130122, People's Republic of China. liuquan1973@hotmail.com.
authors.forename: Quan
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008018:Life Cycle Stages; D051379:Mice; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D014122:Toxoplasma / Q000145:classification / Q000166:cytology* / Q000235:genetics*; D014123:Toxoplasmosis / Q000469:parasitology*
chemical_list: D015800:Protozoan Proteins; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: Intracellular proliferation; TgERK7; Toxoplasma gondii; Toxoplasmosis