Entamoeba histolytica represents a useful model in parasitic organisms due to its complex genomic organization and survival mechanisms. To counteract pathogenic organisms, it is necessary to characterize their molecular biology to design new strategies to combat them. In this report, we investigated a less-known genetic element, short interspersed nuclear element 2 (SINE2), that is present in this ameba and is highly transcribed and polyadenylated. In this study, we show that in two different nonvirulent strains of E. histolytica, SINE2 is differentially processed into two transcript fragments, that is, a full-length 560-nt fragment and a shorter 393-nt fragment bearing an approximately 18-nt polyadenylation tail. Sequence analysis of the SINE2 transcript showed that a Musashi-like protein may bind to it. Also, two putative Musashi-like sequences were identified on the transcript. Semiquantitative expression analysis of the two Musashi-like proteins identified in the E. histolytica genome (XP_648918 and XP_649094) showed that XP_64094 is overexpressed in the nonvirulent strains tested. The information available in the literature and the results presented in this report indicate that SINE2 may affect other genes, as observed with the epigenetic silencing of the G3 strain, by an antisense mechanism or via RNA–protein interactions that may ultimately be involved in the phenotype of nonvirulent strains of E. histolytica.

由于其复杂的基因组组织和生存机制，溶组织内阿米巴代表了寄生生物的有用模型。为了对抗病原生物，有必要对它们的分子生物学进行表征，以设计新的策略来对抗它们。在本报告中，我们研究了一种鲜为人知的遗传元件，即短散在核元件 2 (SINE2)，它存在于该阿米巴虫中，并且高度转录和多聚腺苷酸化。在这项研究中，我们表明在两种不同的无毒力的溶组织大肠杆菌菌株中, SINE2 被不同地加工成两个转录片段，即一个全长 560-nt 片段和一个较短的 393-nt 片段，带有大约 18-nt 聚腺苷酸化尾巴。SINE2 转录本的序列分析表明，可能有一种类似 Musashi 的蛋白质与之结合。此外，在转录本上鉴定了两个假定的 Musashi 样序列。在溶组织大肠杆菌中鉴定的两种 Musashi 样蛋白的半定量表达分析基因组（XP_648918 和 XP_649094）显示 XP_64094 在测试的非毒力菌株中过表达。文献中可用的信息和本报告中提供的结果表明 SINE2 可能影响其他基因，如 G3 菌株的表观遗传沉默所观察到的那样，通过反义机制或通过可能最终参与表型的 RNA-蛋白质相互作用的的无毒毒株溶组织内阿米巴。