溶组织大肠杆菌是肠道阿米巴病和肝脓肿的病因,这仍然构成全球公共卫生威胁。甲硝唑是抗阿米巴病的首选药物。然而,最近报道了耐甲硝唑的阿米巴临床分离株和菌株,挑战根除阿米巴病的努力。为了寻找替代疗法,溶组织大肠杆菌转录组已经显示出参与RNA代谢的基因与寄生虫的毒力的关联。在阿米巴肝脓肿中上调的基因中有剪接因子EhU2AF2和EhSF3B1的旁系。由于这个原因,并且由于EhU2AF2在其延长的C端结构域中包含不寻常的KH-QUA2(84KQ)基序,在这里,我们调查了EhU2AF2在前mRNA处理中的作用如何影响寄生虫的毒力.我们发现84KQ参与几种毒力和非毒力相关基因的剪接抑制/内含子保留。84KQ结构域与组成型剪接因子SF1(SF1KQ)的相同结构域相互作用,在溶液中和当SF1KQ与分支点信号RNA探针结合时。84KQ-SF1KQ相互作用阻止了复杂E到A的剪接过渡,从而抑制拼接。令人惊讶的是,EhU2AF2变形虫转化体中84KQ结构域的缺失增加了剪接并增强了体外和体内毒力表型。我们得出结论,84KQ和SF1KQ域的相互作用,可能涉及其他因素,通过偏爱内含子保留来降低内含子毒力。
E. histolytica is the etiological agent of intestinal amebiasis and liver abscesses, which still poses public health threat globally. Metronidazole is the drug of choice against amebiasis. However, metronidazole-resistant amoebic clinical isolates and strains have been reported recently, challenging the efforts for amebiasis eradication. In search of alternative treatments, E. histolytica transcriptomes have shown the association of genes involved in RNA metabolism with the virulence of the parasite. Among the upregulated genes in amoebic liver abscesses are the splicing factors EhU2AF2 and a paralog of EhSF3B1. For this reason and because EhU2AF2 contains unusual KH-QUA2 (84KQ) motifs in its lengthened C-terminus domain, here we investigated how the role of EhU2AF2 in pre-mRNA processing impacts the virulence of the parasite. We found that 84KQ is involved in splicing inhibition/intron retention of several virulence and non-virulence-related genes. The 84KQ domain interacts with the same domain of the constitutive splicing factor SF1 (SF1KQ), both in solution and when SF1KQ is bound to branchpoint signal RNA probes. The 84KQ-SF1KQ interaction prevents splicing complex E to A transition, thus inhibiting splicing. Surprisingly, the deletion of the 84KQ domain in EhU2AF2 amoeba transformants increased splicing and enhanced the in vitro and in vivo virulence phenotypes. We conclude that the interaction of the 84KQ and SF1KQ domains, probably involving additional factors, tunes down Entamoeba virulence by favoring intron retention.