Zalutskaya Zhanneta, Filina Valentina, Ostroukhova Mariya, Ermilova Elena
Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg, 199034, Russia.
Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg, 199034, Russia.
Eur J Protistol. 2018 Apr;63:26-33. doi: 10.1016/j.ejop.2018.01.001. Epub 2018 Jan 12.
The mitochondrial respiratory chain in plants, some protists and many fungi consists of the ATP-coupling cyanide-sensitive cytochrome pathway and the cyanide-resistant alternative respiratory pathway. The alternative pathway is mediated by alternative oxidase (AOX). Although AOX has been proposed to play essential roles in nutrient stress tolerance of plants and protists, the effects of sulfur (S) deprivation, on AOX are largely unknown. The unicellular green alga Chlamydomonas reinhardtii reacts to S limitation conditions with the induced expression of many genes. In this work, we demonstrated that exposure of C. reinhardtii to S deprivation results in the up-regulation of AOX1 expression and an increased AOX1 protein. Furthermore, S-deprived C. reinhardtii cells display the enhanced AOX1 capacity. Moreover, nitrate assimilation regulatory protein (NIT2) is involved in the control of the AOX1 gene expression in the absence of S. Together, the results clearly indicate that AOX1 relates to S limitation stress responses and is regulated in a NIT2-dependent manner, probably together with yet-unknown regulatory factor(s).
植物、一些原生生物和许多真菌中的线粒体呼吸链由与ATP偶联的对氰化物敏感的细胞色素途径和对氰化物不敏感的交替呼吸途径组成。交替途径由交替氧化酶（AOX）介导。尽管有人提出AOX在植物和原生生物的营养胁迫耐受性中起重要作用，但硫（S）缺乏对AOX的影响在很大程度上尚不清楚。单细胞绿藻莱茵衣藻对S限制条件的反应是许多基因的诱导表达。在这项工作中，我们证明，将莱茵衣藻暴露于S缺乏条件下会导致AOX1表达上调和AOX1蛋白增加。此外，S缺乏的莱茵衣藻细胞显示出增强的AOX1能力。此外，硝酸盐同化调节蛋白（NIT2）在缺乏S的情况下参与AOX1基因表达的控制。总之，结果清楚地表明AOX1与S限制胁迫反应有关，并以NIT2依赖的方式受到调节，可能还与未知的调节因子一起。
