Zinc metalloprotease families in Trypansoma brucei

布氏锥虫中的锌金属蛋白酶家族

• 批准号: 7084393
• 负责人: John E Donelson
• 金额: $ 36.01万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7084393
• 关键词: RNA interference; Trypanosoma brucei; gene deletion mutation; gene expression; immunologic assay /test; laboratory mouse; laboratory rat; metalloendopeptidases; parasite infection mechanism; protein localization; protein structure function; zinc

DESCRIPTION (provided by the applicant): Proteases are critical factors enabling many protozoa and helminths to parasitize and survive in both mammalian and insect hosts. The biological properties and differential expression of related groups of zinc metalloproteases in the African trypanosome Trypanosoma brucei will be studied using the techniques of traditional gene deletion, RNA interference (RNAi), and overexpression for selected experiments. Three groups of metalloproteases, called TbMSP-A, TbMSP-B and TbMSP-C, each has about 33% amino acid identity with the major surface protease (MSP, formerly called GP63) of Leishmania, and share a common zinc binding motif. The mRNAs of all three gene families occur in bloodstream trypanosomes, whereas only the mRNA of TbMSP-B is expressed in procyclic trypanosomes. Their C-terminal amino acid sequences suggest that TbMSP-A and -B are likely associated with a cellular membrane via a glycosylphosphatidylinositol (GPI) anchor, whereas TbMSP-C may be either located in the cytoplasm or secreted. We hypothesize that those TbMSPs predicted on the basis of their sequences to traffic to the trypanosome surface, i.e., TbMSP-A and TbMSP-B, serve important functions in facilitating survival of trypanosomes in the host environment. Our preliminary data lead us to hypothesize that TbMSP-B is a surface protease under translational control in bloodstream cells, which participates in shedding of the variant surface glycoprotein (VSG) during differentiation from bloodstream to procyclic cells. Further evidence leads us to hypothesize that TbMSP-A serves a distinct proteolytic function that is not required in procyclic cells, although the exact nature of this function has yet to be identified. In this application we propose to use the techniques of immunolocalization, sub-cellular fractionation, metabolic labeling, protease characterization, and gene mutagenesis to identify the sub-cellular locations of the TbMSP-A and TbMSP-B families, to determine their biological functions, and to elucidate the molecular mechanisms regulating their differential expression.

描述（由申请人提供）：蛋白酶是许多原生动物和蠕虫在哺乳动物和昆虫宿主中寄生和生存的关键因素。采用传统的基因缺失、RNA干扰（RNAi）和选择性过表达技术研究非洲布氏锥虫锌金属蛋白酶相关类群的生物学特性和差异表达。三组金属蛋白酶，称为tbsp - a， tbsp - b和tbsp - c，每组与利什曼原虫的主要表面蛋白酶（MSP，以前称为GP63）具有约33%的氨基酸同源性，并共享一个共同的锌结合基元。所有三个基因家族的mRNA都出现在血流锥虫中，而只有TbMSP-B的mRNA在前环锥虫中表达。它们的c端氨基酸序列表明，tbsp - a和-B可能通过糖基磷脂酰肌醇（GPI）锚点与细胞膜相关，而tbsp - c可能位于细胞质中或分泌。我们推测，根据其序列预测到的转运到锥虫表面的tbmsp，即TbMSP-A和TbMSP-B，在促进锥虫在宿主环境中的生存中起着重要的作用。