Precision control of protein dosage in vivo

控制组织内特定基因产物剂量的能力支撑了许多现代生物医学科学，从生物途径和疾病机制的基础研究到基因和细胞疗法、疫苗和药物。使用人体组织的实验由于伦理和技术方面的考虑而变得复杂，因此啮齿动物模型被用来促进我们对正常和异常组织功能的理解，并用于测试新的治疗方法。尽管小鼠仍然处于临床前研究的前沿，但需要小鼠遗传学方面的新创新来促进我们对人类疾病机制的理解，确定新的治疗靶点，并更准确地模拟治疗干预措施。蛋白质执行大多数生物功能；然而，蛋白质功能通常是通过在DNA中引入突变来研究的。这有几个缺点。研究DNA突变造成的蛋白质丢失的直接后果是不可能的，因为先前存在的非突变基因产物池可能需要几天时间才能到期。目前的方法并不是研究蛋白质剂量减少的影响的最佳方法，蛋白质剂量减少是许多人类疾病状态的基础，或者允许蛋白质功能被移除然后恢复以模拟治疗干预。在活体小鼠体内快速改变蛋白质剂量的更直接的方法，以一种可以开关的方式，可能会对小鼠用于临床前建模的方式产生革命性的影响。这个集群将结合基因组、蛋白质和小分子工程方面的最新技术发展，以满足这一未得到满足的需求。我们的方法将使用现有的基因工程方法，在感兴趣的蛋白质上添加短的“标签”，称为“退化”。然后，Degron标记的蛋白质可以成为类药物小分子的靶标，这些小分子可以进入细胞并劫持其自然的蛋白质破坏途径，以促进快速、可调和可逆的降解。Degron标签已经在培养的哺乳动物细胞中得到了广泛和成功的应用，它们为细胞如何工作提供了前所未有的见解。然而，在老鼠模型中使用降解物的研究仍处于初级阶段，迫切需要投资来为它们的使用设定标准。例如，在细胞中已经形成了几种不同的退化，但尚不清楚哪一种在不同的小鼠组织和疾病模型中效果最好，或者对特定的治疗干预措施进行建模。不同的小分子可用于降解蛋白质，但这些分子在更复杂的体内环境中的表现尚不清楚。我们认为，MRC国家老鼠遗传学网络是将退化技术转化为人类疾病的老鼠模型的理想论坛。我们的集群汇集了小鼠转基因、蛋白质降解、结构生物学、药物化学和药理学方面的专家，我们已经在两个试点项目中证明了我们的方法是有效的。随着我们进一步开发核心技术，我们将利用该网络在玛丽·里昂中心的支持下与疾病建模方面的国家领导者合作，以改进在小鼠身上建立人类疾病模型的方式。我们共同努力，旨在为在活的哺乳动物中使用退化技术设定标准，并与行业和其他国家利益攸关方进行接触，这些利益相关者将从这些技术的使用中受益。

The ability to control the dose of specific gene products within tissues underpins much of modern biomedical science, ranging from fundamental studies of biological pathways and disease mechanisms to gene and cell therapies, vaccines and pharmaceuticals. Experiments using human tissues are complicated by ethical and technical concerns, and hence rodent models have been used to advance our understanding of normal and abnormal tissue function, and for testing new therapeutic approaches. Although mice remain at the forefront of preclinical studies, new innovations in mouse genetics are needed to advance our understanding of human disease mechanisms, to identify new therapeutic targets, and to more accurately model therapeutic interventions. Proteins carry out most biological functions; however, protein function is typically studied by introducing mutations into DNA. This has several drawbacks. It is not possible to study the immediate consequences of protein loss by mutating DNA, because it can take up to several days for the pre-existing pool of non-mutated gene-products to expire. Current approaches are not optimal to study the impact of reduced protein dose, which underlies many human disease states, or to allow protein function to be removed and then reinstated to model therapeutic intervention. More direct ways to rapidly change protein dose in living mice, in a manner that can be toggled on and off, could have a transformative impact on how mice are used for preclinical modelling.This cluster will combine recent technological developments in the engineering of genomes, proteins and small molecules to address this unmet need. Our approach will use existing genetic engineering approaches to add short 'tags', termed 'degrons', onto proteins of interest. Degron-tagged proteins can then be targeted by small drug-like molecules that can enter cells and hijack their natural protein destruction pathways to facilitate rapid, tuneable and reversible degradation. Degron tags are already widely and successfully used in cultured mammalian cells, where they are providing unprecedented insight into how cells work. However, research using degrons in mouse models remains in its infancy and investment is urgently needed to set standards for their use. For example, several different degrons have been developed in cells, yet it is unclear which will work best in different mouse tissues and disease models, or to model particular therapeutic interventions. Different small molecules are available to degrade proteins with each degron, but how these molecules will behave in the more complex in vivo environment is unclear. We believe that the MRC National Mouse Genetics Network is the ideal forum to translate degron technologies into mouse models of human disease. Our cluster brings together experts in mouse transgenics, protein degradation, structural biology, medicinal chemistry and pharmacology, and we have already shown that our approach works in two pilot projects. As we develop the core technology further, we will use the network to team up with national leaders in disease modelling under the auspices of the Mary Lyon Centre to improve the way that human disease is modelled in mice. Together, we aim to set standards for the use of degron technologies in living mammals and to reach out to industry and other national stakeholders who stand to benefit from their use.