Programa Regional del Noroeste para el Posgrado en Biotecnología de la Facultad de Ciencias Químico-Biológicas, Universidad Autónoma de Sinaloa, Av. de las Américas y Josefa Ortíz (Cd. Universitaria), Culiacán 80030, Mexico.
Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Av. IPN No. 2508, Colonia San Pedro Zacatenco, Mexico City 07360, Mexico.
Int J Environ Res Public Health. 2023 Feb 17;20(4):3556. doi: 10.3390/ijerph20043556.
is a significant cause of waterborne and foodborne infections, day-care center outbreaks, and traveler's diarrhea worldwide. In protozoa such as and iron affects the growth, pathogenicity mechanisms, and expression of virulence genes. One of the proposed iron regulatory mechanisms is at the post-transcriptional level through an IRE/IRP-like (iron responsive element/iron regulatory protein) system. Recently, the expression of many putative giardial virulence factors in the free-iron levels has been reported in subsequent RNAseq experiments; however, the iron regulatory mechanism remains unknown. Thus, this work aimed to determine the effects of iron on the growth, gene expression, and presence of IRE-like structures in . First, the parasite's growth kinetics at different iron concentrations were studied, and the cell viability was determined. It was observed that the parasite can adapt to an iron range from 7.7 to 500 µM; however, in conditions without iron, it is unable to survive in the culture medium. Additionally, the iron modulation of three genes was determined by RT-PCR assays. The results suggested that , , and mRNA were down-regulated by iron. To investigate the presence of IRE-like structures, in silico analyses were performed for different mRNAs from the Giardia genome database. The Zuker mfold v2.4 web server and theoretical analysis were used to predict the secondary structures of the 91 mRNAs analyzed. Interestingly, the iron-induced downregulation of the genes analyzed corresponds to the location of the stem-loop structures found in their UTR regions. In conclusion, iron modulates the growth and expression of specific genes, likely due to the presence of IRE-like structures in mRNAs.
是导致全球食源性和水源性感染、日托中心爆发和旅行者腹泻的重要原因。在原生动物中，如 和 ，铁会影响生长、致病性机制和毒力基因的表达。铁的一种调节机制是在转录后水平上通过 IRE/IRP 样（铁反应元件/铁调节蛋白）系统。最近，在随后的 RNAseq 实验中报道了许多 假定的致病因子在游离铁水平下的表达；然而，铁的调节机制尚不清楚。因此，这项工作旨在确定铁对 的生长、基因表达和 IRE 样结构存在的影响。首先，研究了不同铁浓度下寄生虫的生长动力学，并测定了细胞活力。观察到寄生虫可以适应 7.7 到 500 μM 的铁范围；然而，在没有铁的情况下，它无法在培养基中存活。此外，通过 RT-PCR 测定了三种基因的铁调节。结果表明， 、 和 mRNA 被铁下调。为了研究 IRE 样结构的存在，对来自 基因组数据库的不同 mRNA 进行了计算机分析。使用 Zuker mfold v2.4 网络服务器和理论分析来预测分析的 91 个 mRNA 的二级结构。有趣的是，分析的基因的铁诱导下调与它们 UTR 区域中发现的茎环结构的位置相对应。总之，铁调节特定基因的生长和表达，可能是由于 mRNA 中存在 IRE 样结构。
