León-Sicairos Claudia R, Figueroa-Angulo Elisa E, Calla-Choque Jaeson S, Arroyo Rossana
Department of Infectomics and Molecular Pathogenesis, Center of Research and Advanced Studies of IPN (CINVESTAV-IPN), Av. IPN # 2508, Col. San Pedro Zacatenco, Mexico City 07360, Mexico.
Pathogens. 2023 Apr 12;12(4):586. doi: 10.3390/pathogens12040586.
is one of the most common sexually transmitted parasites in humans. This protozoan has high iron requirements for growth, metabolism, and virulence. However, iron concentrations also differentially modulate gene expression as in the genes encoding cysteine proteinases TvCP4 and TvCP12. Our goal was to identify the regulatory mechanism mediating the upregulation of under iron-restricted (IR) conditions. Here, we showed by RT-PCR, Western blot, and immunocytochemistry assays that IR conditions increase mRNA stability and amount of TvCP12. RNA electrophoretic mobility shift assay (REMSA), UV cross-linking, and competition assays demonstrated that a non-canonical iron-responsive element (IRE)-like structure at the 3'-untranslated region of the transcript (IRE-tvcp12) specifically binds to human iron regulatory proteins (IRPs) and to atypical RNA-binding cytoplasmic proteins from IR trichomonads, such as HSP70 and α-Actinin 3. These data were confirmed by REMSA supershift and Northwestern blot assays. Thus, our findings show that a positive gene expression regulation under IR conditions occurs at the posttranscriptional level possibly through RNA-protein interactions between atypical RNA-binding proteins and non-canonical IRE-like structures at the 3'-UTR of the transcript by a parallel mechanism to the mammalian IRE/IRP system that can be applied to other iron-regulated genes of
是人类最常见的性传播寄生虫之一。这种原生动物在生长、代谢和毒力方面对铁有很高的需求。然而，铁浓度也会差异性地调节基因表达，如在编码半胱氨酸蛋白酶TvCP4和TvCP12的基因中。我们的目标是确定在铁限制（IR）条件下介导 上调的调控机制。在这里，我们通过RT-PCR、蛋白质免疫印迹和免疫细胞化学分析表明，IR条件会增加TvCP12的mRNA稳定性和数量。RNA电泳迁移率变动分析（REMSA）、紫外线交联和竞争分析表明，转录本3'非翻译区的一个非经典铁反应元件（IRE）样结构（IRE-tvcp12）特异性结合人铁调节蛋白（IRP）以及来自IR滴虫的非典型RNA结合细胞质蛋白，如HSP70和α-辅肌动蛋白3。这些数据通过REMSA超迁移和蛋白质印迹分析得到证实。因此，我们的研究结果表明，IR条件下的正性基因表达调控发生在转录后水平，可能是通过非典型RNA结合蛋白与转录本3'-UTR处的非经典IRE样结构之间的RNA-蛋白质相互作用，其机制与哺乳动物IRE/IRP系统平行，可应用于 的其他铁调节基因。
