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.

几乎所有人类医学中使用的抗生素都是 50 年前发现的，大多数致病细菌现在对其中一种或多种药物具有耐药性。这意味着人类正面临着回到抗生素前时代的危险，这种情况被称为“抗生素末日”。政府委托奥尼尔对抗菌素耐药性 (AMR) 进行审查，估计如果我们现在不启动抗生素发现工作，那么到 2050 年，耐药性感染导致的死亡人数将超过癌症，估计每年有 1000 万人死亡。我们目前使用的大多数抗生素都是源自土壤细菌次生代谢产物的天然产物，其中最重要的一类称为链霉菌，它产生了所有已知抗生素的 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了真正容易找到的化合物，即唾手可得的果实。过去 15 年的基因组测序显示，链霉菌在实验室条件下仅产生约 25% 的次生代谢物，这意味着从 1940-60 年（所谓的抗生素发现黄金时代），科学家们几乎没有对其能力进行采样。其余的被称为“沉默的”次生代谢物，因为它们不是在实验室中制造的。好消息是，这意味着我们比 20 世纪的科学家有很大的优势 - 如果我们能找到方法来启动超过 600 种已知物种中所有沉默的次级代谢产物的生产，我们将发现许多可以进入的新抗生素临床试验管道。这是抗生素发现的最早阶段，我们现在加大努力至关重要，因为药物通过临床试验并批准用于人类需要 10-15 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从链霉菌中发现的天然产品越多越好。激活沉默次生代谢物产生的一种方法是了解控制其在土壤中产生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，我们就可以迫使细菌在实验室中制造所有抗生素。理想情况下，我们希望确定影响所有 600 多种已知链霉菌物种抗生素生产的信号通路，这就是我们提案的主题。我们鉴定了一条由 MtrA 和 MtrB 两种蛋白组成的信号通路，并发现这是链霉菌属中唯一保守且必需的通路。这意味着这种 MtrAB 双组分系统存在于每个已测序的链霉菌菌株中！ MtrA 是一种 DNA 结合蛋白，其活性受信号传感蛋白 MtrB 控制。如果我们通过删除 mtrA 基因来破坏该通路，那么它是致命的。如果我们删除 mtrB 基因，它就不再需要环境信号来激活该途径，并导致活性 MtrA 蛋白的过量产生，从而开启抗生素的产生，而这些抗生素在野生型菌株中通常是沉默的。然而，仅仅过度生产 MtrA 是行不通的，我们还必须删除 MtrB。在本项目中，我们将分析两种模型物种（S. coelicolor 和 S. venezuelae）中的 MtrAB。我们将确定 MtrB 如何控制 MtrA 活性、为什么 MtrA 在没有 MtrB 的情况下具有活性以及 MtrA 为何以及如何激活沉默次级代谢产物的产生。我们还将尝试获得始终活跃的 MtrA 蛋白的功能，看看是否可以使用它们在我们的模型菌株和我们已分离并进行基因组测序的两个新的有天赋的链霉菌物种中启动抗生素生产。我们称它们为天才，因为它们似乎编码许多新颖的次级代谢物，而 MtrA 可能使我们能够从这些菌株中发现新的抗生素。

项目成果

Sensing and responding to diverse extracellular signals: an updated analysis of the sensor kinases and response regulators of Streptomyces species.

感知和响应不同的细胞外信号：链霉菌属传感器激酶和响应调节剂的最新分析。

• DOI: http://dx.10.1099/mic.0.000817
• 发表时间: 2019
• 期刊: Microbiology (Reading, England)
• 作者: McLean TC

ActinoBase: tools and protocols for researchers working on Streptomyces and other filamentous actinobacteria.

ActinoBase：为研究链霉菌和其他丝状放线菌的研究人员提供的工具和协议。

• DOI: http://dx.10.1099/mgen.0.000824
• 发表时间: 2022
• 期刊: Microbial genomics
• 影响因子: 3.9
• 作者: Feeney MA

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

MtrAB 双组分系统控制天蓝色链霉菌 A3(2) 中抗生素的产生。

• DOI: http://dx.10.1099/mic.0.000524
• 发表时间: 2017
• 期刊: Microbiology (Reading, England)
• 作者: Som NF

Dissolution of the Disparate: Co-ordinate Regulation in Antibiotic Biosynthesis.

不同的溶解：抗生素生物合成的协调调节。

• DOI: http://dx.10.3390/antibiotics8020083
• 发表时间: 2019
• 期刊: Antibiotics (Basel, Switzerland)
• 作者: McLean TC

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

保守的放线菌双组分系统 MtrAB 协调委内瑞拉链霉菌 NRRL B-65442 中氯霉素的生产和孢子形成。

• DOI: http://dx.10.3389/fmicb.2017.01145
• 发表时间: 2017
• 期刊: Frontiers in microbiology
• 作者: Som NF