Understanding and manipulating a conserved and essential transcription factor to activate antibiotic production in Streptomyces species

了解和操纵保守且必需的转录因子以激活链霉菌物种中的抗生素生产

• 批准号: BB/P005292/1
• 负责人: Matthew Hutchings
• 金额: $ 51.77万
• 依托单位: University of East Anglia
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FP005292%2F1
• 关键词: Understanding; manipulating; conserved; essential; transcription

Almost all the antibiotics used in human medicine were discovered >50 years ago and most disease-causing bacteria are now resistant to one or more of these drugs. This means humans are facing a return to the pre-antibiotic era, an alarming situation that has been described as 'antibiotic Armageddon'. The government commissioned O'Neill review on AntiMicrobial Resistance (AMR) estimates that if we do not kick-start antibiotic discovery efforts now then by 2050 drug resistant infections will kill more people than cancer, an estimated 10 million a year. Most of the antibiotics we currently use are natural products derived from the secondary metabolites of soil bacteria and the most important group are called Streptomyces, which make 50% of all known antibiotics. Streptomyces are incredibly important to humans and although scientists have already discovered lots of antibiotics from these bacteria we now know that they only found the really easy to find compounds, the low hanging fruit. Genome sequencing over the last 15 years has revealed that Streptomyces bacteria only make about 25% of their secondary metabolites under laboratory conditions which means that from 1940-60, the so-called golden age of antibiotic discovery, scientists were barely sampling their capability. The rest are called 'silent' secondary metabolites because they do not make them in the lab. The good news is this means we have a big advantage over scientists working in the 20th century - if we can find ways to switch on production of all the silent secondary metabolites in the >600 known species we will find lots of new antibiotics that can enter the clinical trials pipeline. This is the earliest stage in antibiotic discovery and it is vital that we increase our efforts now because it takes 10-15 years to get drugs through clinical trials and approved for use in humans. Probably <1% of antibiotics will be suitable for treating disease so the more natural products we can discover from Streptomyces in the next few decades the better. One way to activate the production of silent secondary metabolites is to understand the natural signals and signalling pathways that control their production in the soil and this is the focus of our research. If we can manipulate those signalling pathways we can force the bacteria to make all of their antibiotics in the laboratory. Ideally we want to identify signalling pathways which effect antibiotic production in all 600+ known Streptomyces species and this is the subject of our proposal. We have identified a signalling pathway consisting of two proteins called MtrA and MtrB and found this is the only conserved and essential pathway in the genus Streptomyces. This means this MtrAB two-component system is found in every single sequenced Streptomyces strain! MtrA is a DNA binding protein and its activity is controlled by the signal sensing protein MtrB. If we disrupt the pathway by deleting the mtrA gene it is lethal. If we delete the mtrB gene it removes the need for an environmental signal to activate the pathway and results in over-production of active MtrA protein which switches on production of antibiotics that are usually silent in the wild-type strains. However, simply over-producing MtrA does not work, we HAVE to remove MtrB as well. In this project we will analyse MtrAB in two model species called S. coelicolor and S. venezuelae. We will determine how MtrB controls MtrA activity, why MtrA is active in the absence of MtrB and why and how MtrA activates the production of silent secondary metabolites. We will also try to make gain of function MtrA proteins that are always active and see if we can use them to switch on antibiotic production in our model strains and in two new talented Streptomyces species that we have isolated and genome sequenced. We call them talented because they appear to encode many novel secondary metabolites and MtrA may allow us to discover new antibiotics from these strains.

几乎所有用于人类医学中使用的抗生素都是> 50年前发现的，大多数引起疾病的细菌现在对其中一种或多种药物具有抗药性。这意味着人类正面临重返抗生素前时代的恢复，这是一个令人震惊的情况，被称为“抗生素大决战”。政府对奥尼尔抗菌抗性（AMR）进行了委托评论，估计，如果我们现在不开始启动抗生素发现工作，那么到2050年，抗药性感染将杀死比癌症更多的人，估计每年1000万。我们目前使用的大多数抗生素是源自土壤细菌的二级代谢产物的天然产物，最重要的基团称为链霉菌，它们占所有已知抗生素的50％。链霉菌对人类非常重要，尽管科学家已经从这些细菌中发现了许多抗生素，但我们现在知道他们只发现很容易找到化合物，低悬挂的水果。在过去的15年中，基因组测序表明，在实验室条件下，链霉菌细菌仅占其次生代谢物的25％，这意味着从1940 - 60年开始，所谓的抗生素发现黄金时代，科学家几乎没有取样其能力。其余的称为“沉默”次生代谢物，因为它们不在实验室中。好消息是，这意味着我们比20世纪的科学家拥有很大的优势 - 如果我们能找到> 600种已知物种中所有沉默的次级代谢产物的生产方法，我们会发现许多可以进入临床试验管道的新抗生素。这是抗生素发现中最早的阶段，现在至关重要的是，我们现在可以增加努力，因为通过临床试验获得药物并批准用于人类需要10到15年的时间。可能<1％的抗生素适合治疗疾病，因此我们在未来几十年中可以从链霉菌中发现的天然产品越多越好。激活无声次级代谢产物产生的一种方法是了解控制土壤中生产的自然信号和信号通路，这是我们研究的重点。如果我们能够操纵这些信号通路，我们可以迫使细菌使其在实验室中制成所有抗生素。理想情况下，我们希望确定在所有600多种已知链霉菌物种中影响抗生素产生的信号通路，这是我们建议的主题。我们已经确定了一个由两个称为MTRA和MTRB的蛋白质组成的信号通路，发现这是链霉菌属中唯一保守和必不可少的途径。这意味着在每个测序的链霉菌菌株中都可以找到此MTRAB两组分系统！ MTRA是一种DNA结合蛋白，其活性由信号传感蛋白MTRB控制。如果我们通过删除MTRA基因来破坏该路径，那将是致命的。如果我们删除MTRB基因，则消除了对环境信号激活途径的需求，并导致活性MTRA蛋白过量产生，该蛋白会切换通常在野生型菌株中保持沉默的抗生素的产生。但是，仅产生过度的MTRA就无法使用，我们也必须删除MTRB。在这个项目中，我们将分析两个模型物种中的MTRAB，称为Coelicolor S. coelicolor和S. venezuelae。我们将确定MTRB如何控制MTRA活性，为什么MTRA在没有MTRB的情况下活跃，以及为什么以及MTRA如何激活沉默的二级代谢产物的产生。我们还将尝试获得始终活跃的功能MTRA蛋白，并查看是否可以使用它们在模型菌株中开启抗生素产生，以及我们已经分离并测序的两个新的才华横溢的链霉菌物种。我们之所以称它们为才华，是因为它们似乎编码了许多新型的次要代谢产物，而MTRA可能会使我们从这些菌株中发现新的抗生素。

项目成果

The Conserved Actinobacterial Two-Component System MtrAB Coordinates Chloramphenicol Production with Sporulation in Streptomyces venezuelae NRRL B-65442.

• DOI: 10.3389/fmicb.2017.01145
• 发表时间: 2017
• 期刊: Frontiers in microbiology
• 影响因子: 5.2
• 作者: Som NF;Heine D;Holmes NA;Munnoch JT;Chandra G;Seipke RF;Hoskisson PA;Wilkinson B;Hutchings MI
• 通讯作者: Hutchings MI

The MtrAB two-component system controls antibiotic production in Streptomyces coelicolor A3(2).

• DOI: 10.1099/mic.0.000524
• 发表时间: 2017-10
• 期刊: Microbiology (Reading, England)
• 作者: Som NF;Heine D;Holmes N;Knowles F;Chandra G;Seipke RF;Hoskisson PA;Wilkinson B;Hutchings MI
• 通讯作者: Hutchings MI