Identification and characterization of type III secretion system (T3SS) effectors in Edwardsiella tarda

迟缓爱德华氏菌 III 型分泌系统 (T3SS) 效应子的鉴定和表征

• 批准号: RGPIN-2014-06385
• 负责人: Leung, KaYin
• 金额: $ 2.55万
• 依托单位: Trinity Western University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=588973
• 关键词: Identification; characterization; type; III; secretion

Aquaculture is a one-billion-dollars business in Canada and it provides about 15,000 full time well-paid jobs in many rural and coastal communities. In 2011, Canada was the fifth largest seafood exporter globally. The aquaculture industry is a significant contributor to the stable and strong Canadian economy; it also provides food security as well as healthy food for the Canadian population. Unfortunately, fish diseases are major challenges to the sustainability and viability of the aquaculture industry. Research in this area is urgently needed not only to support the local industry but also other enterprises around the world. Understanding how pathogens infect and live inside fish cells and tissues, and how they spread throughout the whole fish can lead to the development of adequate control measures and other biotechnological applications. Bacteria secrete proteins into the surrounding environment or host cells to allow them to gain a competitive advantage or to facilitate entry into and survival inside the hosts. At least seven different types of bacterial protein secretion systems, named type I to VII, exist. These systems release disease-causing proteins into their surroundings, directly into host cells, or even to other bacteria found in the same environment. These proteins target specific host proteins and alter their biological functions to gain control of the host. Among the different labs in the world studying bacterial secretion systems, our lab has considerable expertise on both type III and type VI secretion systems (T3SS and T6SS) found in the bacterium Edwardsiella tarda. E. tarda is abundant in water environments and is a common and important pathogen of freshwater and marine fish. The disease properties of E. tarda are due in large part to their T3SS and T6SS. The genome of E. tarda has been decoded. The proposed study seeks to identify and characterize T3SS disease-causing proteins in E. tarda. On average there are 20-30 disease-causing bacterial proteins secreted from a T3SS. E. tarda encodes about 3,700 proteins and 1,000+ of them are classified as potentially new proteins. Our first aim is to identify the T3SS disease-causing proteins from the 1,000+ new proteins. We will use a bioinformatics approach to predict T3SS disease-causing proteins based on their secretion signals. A computing program will be trained for the prediction of T3SS disease-causing proteins. Once we have an adequate program, it will be used to screen the 1,000+ new proteins of E. tarda to shortlist the candidates to about 50. These candidates will be validated using our established protocols for the confirmation of T3SS delivery. The second aim is to characterize the functions of the identified T3SS disease-causing proteins. We would like to find out the targeted host proteins that interact with these bacterial proteins, the physiological functions that these bacterial proteins disrupt or mimic in the host cells, the precise roles of the bacterial proteins at the cellular and molecular levels, and how they collectively and individually contribute to the disease-causing process in fish. With my expertise on bacterial secretion systems and a strong multidisciplinary team, I am confident that we will complete the objectives outlined in this proposal. Potential biotechnological applications include the development of vaccines and novel therapeutics to prevent diseases in fish. This research will not only promote a knowledge-based economy in Canada, but will also have global importance.

水产养殖在加拿大是一项价值 10 亿美元的产业，为许多农村和沿海社区提供了约 15,000 个全职高薪工作岗位。 2011年，加拿大是全球第五大海鲜出口国。水产养殖业是加拿大经济稳定和强劲的重要贡献者；它还为加拿大人民提供粮食安全和健康食品。不幸的是，鱼病是水产养殖业可持续性和生存能力的主要挑战。迫切需要该领域的研究，不仅可以支持当地行业，还可以支持世界各地的其他企业。了解病原体如何感染并在鱼类细胞和组织内生存，以及它们如何在整个鱼类中传播，可以帮助制定适当的控制措施和其他生物技术应用。 细菌将蛋白质分泌到周围环境或宿主细胞中，以使它们获得竞争优势或促进进入宿主并在宿主体内生存。至少存在七种不同类型的细菌蛋白质分泌系统，称为 I 型至 VII 型。这些系统将致病蛋白质释放到周围环境中，直接释放到宿主细胞中，甚至释放到同一环境中发现的其他细菌中。这些蛋白质针对特定的宿主蛋白质并改变其生物功能以控制宿主。在世界上研究细菌分泌系统的不同实验室中，我们的实验室在迟缓爱德华氏菌中发现的 III 型和 VI 型分泌系统（T3SS 和 T6SS）方面拥有丰富的专业知识。 E. tarda在水环境中大量存在，是淡水和海水鱼类常见且重要的病原体。 E. tarda 的疾病特性在很大程度上归因于其 T3SS 和 T6SS。 E. tarda 的基因组已被破译。拟议的研究旨在鉴定和表征 E. tarda 中的 T3SS 致病蛋白。 T3SS 平均分泌 20-30 种致病细菌蛋白。 E. tarda 编码约 3,700 种蛋白质，其中 1,000 多种被归类为潜在新蛋白质。我们的首要目标是从 1,000 多种新蛋白质中识别 T3SS 致病蛋白质。我们将使用生物信息学方法根据 T3SS 致病蛋白的分泌信号来预测它们。将训练一个计算程序来预测 T3SS 致病蛋白。一旦我们有了适当的程序，它将用于筛选 1,000 多种 E. tarda 新蛋白，从而将候选蛋白列入大约 50 种候选蛋白。这些候选蛋白将使用我们既定的协议进行验证，以确认 T3SS 交付。第二个目标是表征已识别的 T3SS 致病蛋白的功能。我们希望找出与这些细菌蛋白相互作用的目标宿主蛋白、这些细菌蛋白在宿主细胞中破坏或模拟的生理功能、细菌蛋白在细胞和分子水平上的精确作用，以及它们如何共同发挥作用。并单独促进鱼类的致病过程。 凭借我在细菌分泌系统方面的专业知识和强大的多学科团队，我相信我们将完成本提案中概述的目标。潜在的生物技术应用包括开发预防鱼类疾病的疫苗和新疗法。这项研究不仅将促进加拿大的知识经济，而且具有全球重要性。