Regulation of rRNA transcription in Entamoeba histolyti*

溶组织内阿米巴 rRNA 转录的调控*

• 批准号: 6401319
• 负责人: William A Petri
• 金额: $ 3.79万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6401319
• 关键词: DNA binding protein; Entamoeba histolytica; Plasmodium falciparum; RNA directed DNA polymerase; cooperative study; gene deletion mutation; gene expression; genetic enhancer element; genetic mapping; genetic promoter element; genetic regulation; genetic regulatory element; genetic strain; genetic transcription; nucleic acid sequence; plasmids; protozoal genetics; recombinant DNA; ribosomal DNA; ribosomal RNA

DESCRIPTION (provided by applicant) The aim of this proposal is to locate the regulatory elements required for transcription of rRNA genes in Entamoeba histolytica. Transcription of rDNA in E. histolytica is expected to be novel due to- A) the unusual arrangement of rRNA genes in this organism. These genes are exclusively episomal with no evidence of a chromosomal copy. It is known that in yeast, under conditions where the rRNA genes are episomal, these are transcribed by RNA polymerase II in place of Pol I and cryptic Pol II promoters of rRNA genes have been demonstrated (Conrad-Webb and Butow, 1995). B) The rDNA episome in some E. histolytica strains contains two rDNA units arranged as inverted repeats. The sequences upstream of the two rDNA units which normally contain the transcriptional regulatory elements are completely different from each other. This is a novel feature since in most organisms the multiple copies of rRNA genes have exactly identical upstream and downstream intergenic spacers. A notable exception is the protozoan parasite Plasmodium falciparum which contains two distinct classes of rRNA genes that are differentially expressed at different stages of the life cycle (Waters et at., 1989). In E. histolytica since the two rDNA units do not have identical upstream sequences it would be interesting to see if the two units are differentially expressed. Once the rDNA promoter and enhancer elements are identified these may be utilized for over expression of transfected genes in E. histolytica if the promoter strength is superior to the promoters currently used in E. histolytica vectors. In addition it is envisaged that knowledge about the protein factors that regulate rDNA transcription may provide novel drug targets to interfere with this essential process.

描述(由申请人提供) 本提案的目的是确定以下所需的监管要素 溶组织内阿米巴rRNA基因的转录。RDNA在细胞中的转录 由于-A)不同寻常的排列，溶解组织E.org有望成为新的 这种有机体中的rRNA基因。这些基因完全是异构体，没有 染色体复制的证据。众所周知，在酵母中，在条件下， 在rrna基因是异构体的地方，这些基因由rna聚合酶ii转录。 RRNA基因的启动子已经取代了POL I和POL II 演示(Conrad-Webb和Butow，1995)。B)在一些E. 溶组织型菌株含有两个以反向重复序列排列的rDNA单位。这个 两个rDNA单位上游的序列，这两个单位通常包含 转录调控元件之间是完全不同的。 这是一个新的特征，因为在大多数生物体中，rRNA的多个拷贝 基因具有完全相同的上游和下游基因间隔区。一个 值得注意的例外是原生动物寄生虫恶性疟原虫 包含两类不同的差异表达的rRNA基因 在生命周期的不同阶段(Waters et at.，)。在溶组织乳杆菌中 由于两个rDNA单元没有相同的上游序列，因此 有趣的是，这两个单位是否有不同的表达方式。一旦rDNA 确定了启动子和增强子元件，这些元件可能被利用超过 启动子强度为3的情况下基因在溶组织大肠杆菌中的表达 优于目前用于溶组织埃希氏菌载体的启动子。此外 据设想，关于调节rDNA的蛋白质因素的知识 转录可能提供新的药物靶点来干扰这一必要的 进程。