GENE EXPRESSION/DRUG RESISTANCE IN TRICHOMONAS

本研究的长期目标是了解寄生虫阴道毛滴虫中基因表达的基本特性，研究甲硝唑耐药寄生虫中基因表达改变的作用，并确定耐药机制。 T.迷走神经是美国人最常见的寄生虫之一。 这种寄生虫的分离株，是难治的治疗与甲硝唑，唯一的药物许可的治疗，经常报告。 我们以前的研究提供了证据表明，耐药菌株已经改变了编码蛋白质的基因的转录，这些蛋白质是将这种前药活化为其细胞毒性形式所必需的。 研究了T.迷走神经以及这些机制如何改变以产生耐药性，导致我们发现了一个高度保守的必需启动子元件（Inr），该元件是所有T.编码迷走蛋白的基因。 我们建议定义这个元件及其相互作用的蛋白质在启动转录的作用。 可能的新机制用于翻译T。还将检查迷走神经蛋白。 由于我们的研究重点是寄生虫的特性，使其与人类宿主区分开来，因此所获得的信息可能会导致识别新的治疗靶点。 本研究拟通过以下方法扩展基因表达与耐药性的研究：（1）通过纯化和克隆编码该蛋白的基因来鉴定与Inr启动子元件特异性结合的蛋白质;（2）研究不常见的mRNA 5'非翻译区在T.（3）确定改变的基因表达是否是毛滴虫耐药性的原因。 这些研究将极大地增强我们对早期进化真核生物基因表达的理解。 此外，更好地了解毛滴虫基因表达的基本特性，将提供深入了解寄生原生生物的基因调控机制的演变，以及产生耐药性的生化机制。

The long term objectives of this research are to understand the basic properties that are critical for the expression of genes in the parasite Trichomonas vaginalis, to examine the role of altered gene expression in metronidazole resistant parasites and to determine the mechanism underlying drug resistance. T. vaginalis is one of the most common parasites encountered by Americans. Isolates of this parasite that are refractory to treatment with metronidazole, the only drug licensed for therapy, are frequently reported. Our previous research has provided evidence that drug resistant strains have altered transcription of genes encoding proteins that are necessary for activation of this prodrug to its cytotoxic form. Investigation of the mechanisms that govern transcription in T. vaginalis and how these mechanisms can be altered to give rise to drug resistance has lead to our discovery of a highly conserved, essential promoter element (Inr) that is necessary for transcription of all T. vaginalis protein-coding genes. We propose to define the role of this element and its interacting proteins in initiation of transcription. Possible novel mechanisms used for the translation of T. vaginalis proteins will also be examined. As our studies focus on properties of the parasite that distinguish it from its human host, the information gained may lead to identification of novel, therapeutic targets. We propose to extend our research on gene expression and drug resistance by (1) characterizing a protein that specifically binds to the essential Inr promoter element by purifying the protein and cloning the gene encoding this protein, (2) examining the role of the unusual 5' untranslated regions of mRNAs in expression of T. vaginalis genes and (3) determining whether altered gene expression is responsible for drug resistance in trichomonads. These studies will greatly enhance our understanding of gene expression in early-evolving eukaryotes. Moreover, a better understanding of the basic properties underlying gene expression in trichomonads will provide insights into the evolution of gene regulatory mechanisms in parasitic protists, as well as biochemical mechanisms that give rise to drug resistance.