Identification and characterization of stearoyl-CoA desaturase in Toxoplasma gondii  

作　　者：Pan Hao Xia Cui Jing Liu Muzi Li Yong Fu Qun Liu 

机构地区：[1]National Animal Protozoa Laboratory,College of Veterinary Medicine,China Agricultural University, Beijing 100093,China [2]Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture,College of Veterinary Medicine,China Agricultural University, Beijing 100093,China [3]Patent Examination Cooperation Sichuan Center of the Patent Office,CNIPA,Chengdu 610213, China [4]Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Research Centre for Preventive Medicine, Beijing 100013,China

出　　处：《Acta Biochimica et Biophysica Sinica》2019年第6期615-626,共12页生物化学与生物物理学报（英文版）

基　　金：This work was supported by the National Key Research and Development Program of China (2017YFD0500400);the National Natural Science Foundation of China (31372424 and 31672544).We greatly appreciate Prof. William J.Sullivan,Jr.(Indiana University,USA) for providing TgIF2a antibodies, whose research was funded by National Institutes of Health grant AI105786.

摘　　要：Few information of the function of stearoyl-coenzyme A (CoA) desaturase (SCD) in apicomplaxan parasite has been obtained. In this study, we retrieved a putative fatty acyl-CoA desaturase (TGGT1_238950) by a protein alignment with Plasmodium falciparum SCD in ToxoDB. A typical △9-desaturase domain was revealed in this protein. The putative desaturase was tagged with HA endogenously in Toxoplasma gondii, and the endoplasmic reticulum localization of the putative desaturase was revealed, which was consistent with the fatty acid desaturases in other organisms. Therefore, the TGGT1_238950 was designated T gondii SCD. Based on CRISPR/Cas9 gene editing tech no logy, SCD conditional kno ckout muta nts in the T gondii TATi strai n were obtai ned. The growth in vitro and pathogenicity in mice of the mutants suggested that SCD might be dispensable for tachyzoite growth and proliferation. The SCD-overexpressing line was constructed to further explore SCD function.The portion of palmitoleic acid and oleic acid were increased in SCD-overexpressi ng parasites,compared with the RH pare ntal strai n, indicati ng that T.gondii in deed is compete nt for unsaturated fatty acid synthesis.The SCD-overexpressing tachyzoites propagated slower than the parental strain,with a decreased invasion capability and weaker pathogenicity in mice. The TglF2α phosphorylation and the expression changes of several genes demonstrated that ER stress was triggered in the SCD-overexpressing parasites,which were more apt toward autophagy and apoptosis. The function of unsaturated fatty acid synthesis of TgSCD was consistent with our hypothesis.On the other hand,SCD might also be involved in tachyzoite autophagy and apoptosis.

关 键 词：TOXOPLASMA GONDII stearoyl-coenzyme A DESATURASE gene EDITING AUTOPHAGY endoplasmic reticulum stress 

分 类 号：Q[生物学]