GAMETOCYTE STAGE TRANSCRIPTION IN P FALCIPARUM

恶性疟原虫配子细胞阶段转录

• 批准号: 2068525
• 负责人: LAURA G POLOGE
• 金额: $ 10.84万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-12-01 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2068525
• 关键词: Plasmodium falciparum; artificial chromosomes; gametogenesis; gene expression; gene induction /repression; genetic regulatory element; genetic transcription; immunofluorescence technique; microorganism genetics; molecular cloning; nucleic acid hybridization; nucleic acid probes; nucleic acid sequence; polymerase chain reaction; pulsed field gel electrophoresis; restriction mapping; sex differentiation; southern blotting; sporogenesis

The human malaria parasite, Plasmodium falciparum, is transmitted by a mosquito vector, which consumes infected red blood cells from one individual, and after sexual development and sporogony of the parasite, injects infectious sporozoites into another individual. Not all blood stage parasites are competent to develop in the mosquito. Asexual blood stage parasites can only complete their life cycle in the human host, giving rise to more parasites and the clinical symptoms of malaria. Other blood stage parasites differentiate sexually into male and female gametocytes that can continue developing only in the mosquito. Expression of unique gametocyte stage genes is necessary for sexual differentiation and successful mosquito transmission. The long term objective of this research proposal is to produce a physical map of the stage specific transcriptional activity along large continuous stretches of DNA (tens to hundreds of kB) flanking two model gametocyte stage genes, the pfs16 and pfg27/25 genes. These genes are transcribed exclusively in the sexual stages. In laboratory isolates which have lost the capacity to differentiate sexually and complete their life cycle, the pfs16 and pfg27/25 genes are not transcribed. I propose to isolate these genes on yeast artificial chromosomes (YACs) to test the hypothesis that sexual stage genes are coordinately transcribed. Asexual and gametocyte stage cDNA or RNA probes will identify and determine the stage specificity of new blood stage transcription units on the YAC clones around the model gametocyte stage genes. This unique approach may identify new gametocyte stage antigens as potential targets for transmission blocking immunity. We have identified a mutant P. falciparum isolate in which the pfg27/25 gene is aberrantly transcribed in the asexual stages. Comparison of the transcriptional environment around the gene in wild type asexual parasites and in the mutant will determine whether inappropriate activation of a gene modifies the transcriptional stage of nearby genes.

人类疟疾寄生虫疟原虫恶性疟原虫是由A传播的 蚊子载体消耗从一个消耗感染的红细胞 个人，以及在寄生虫的性发展和孢子形成之后 将传染性的孢子虫注入另一个人。 并非所有的血 阶段寄生虫有能力在蚊子中发展。 无性血 舞台寄生虫只能在人类宿主中完成他们的生命周期， 引起更多寄生虫和疟疾的临床症状。 其他血级寄生虫将性别分为男性和女性 只能在蚊子中继续发展的配子细胞。 独特的配子细胞阶段基因的表达对于性是必要的 分化和成功的蚊子传播。 该研究建议的长期目标是产生 阶段特定转录活动的物理图沿大型 连续的DNA（数十至数百kb）的侧面两种模型 配子细胞阶段基因，PFS16和PFG27/25基因。 这些基因是 仅在性阶段转录。 在实验室分离株中 失去了分化性和完成他们的能力的能力 生命周期，PFS16和PFG27/25基因未转录。 我建议 在酵母人工染色体（YAC）上分离这些基因以测试 性阶段基因是协调转录的假设。 无性 配子细胞阶段cDNA或RNA探针将识别并确定 YAC上新血液阶段转录单元的阶段特异性 围绕模型配子细胞阶段基因的克隆。 这种独特的方法可能 识别新的配子细胞阶段抗原作为潜在的靶标 传输阻断免疫力。 我们已经确定了一个突变的恶性疟原虫分离株，其中PFG27/25在其中 基因在无性阶段异常转录。 比较 野生类型的基因周围的转录环境 寄生虫和突变体将确定不适当 基因的激活修饰了附近基因的转录阶段。