Investigating the function of Hindsight/RREB-1 in the intestinal stem cell lineage of Drosophila

研究 Hindsight/RREB-1 在果蝇肠道干细胞谱系中的功能

• 批准号: RGPIN-2015-04458
• 负责人: Reed, Bruce
• 金额: $ 2.77万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=687145
• 关键词: Investigating; function; Hindsight; RREB; intestinal

Stem cells are undifferentiated cells that have the ability of self-renewal as well as the capacity to differentiate into specialized cell types. Understanding the regulation of adult stem cells is a very active area of research, and the possibility of using stem cells to treat injury or disease represents the foundation of the new concept of "regenerative medicine".***It has only recently been established that the fruit fly (Drosophila), despite having a lifespan of only 45-60 days, houses stem cells within differentiated adult tissues.  For example, as in mammals, old or damaged differentiated cells in the gut epithelium are constantly shed and lost, and the replacement of these cells depends on the activity of a population of intestinal stem cells (ISCs) that reside throughout the gut epithelium. Interestingly, many genes and mechanisms regulating ISCs are conserved between Drosophila and mammals. Research using Drosophila has several advantages, including powerful and sophisticated genetic techniques, and these tools can now be applied to fundamental questions regarding the function and behaviour of stem cells.*** In the Drosophila midgut, ISCs divide to produce one daughter cell that retains the ISC identity and a second committed daughter cell known as an enteroblast (EB). EB differentiation occurs without further cell division, and EBs may become either absorptive enterocytes (ECs) or secretory enteroendocrine cells (EEs). My NSERC-funded research has involved investigating the function of the C2H2 type Zinc-finger transcription factor encoded by the gene hindsight. We recently found that hindsight is expressed in all midgut cell types. ISCs, EBs, and EEs, however, are associated with lower levels of Hindsight than differentiated ECs. In addition, we have found that RNAi-mediated depletion of Hindsight results in the loss of all ISCs, and, strikingly, that increasing the level of Hindsight is both necessary and sufficient for EC differentiation.*** This proposal outlines experiments to elucidate the role of Hindsight in ISCs and differentiated ECs. For example, why is Hindsight required for ISC maintenance? What happens to ISCs as they are "lost"? And what is the function of Hindsight in mature differentiated ECs? In addition to addressing these questions, we also propose experiments to better understand the function of Hindsight, which is the Drosophila homologue of human Ras Responsive Element Binding protein-1 (RREB-1). There is some evidence that Hindsight is modified by phosphorylation, and we propose investigating how Hindsight function might be affected by such modification. RREB-1 has been implicated in pancreatic, thyroid, and colon cancer - and basic research of its homologue in the Drosophila will not only advance the understanding of RREB-1 function in humans, but may ultimately contribute to developing novel approaches for treating these forms of cancer. **

干细胞是没有分化的细胞，具有自我更新的能力以及分化为专用细胞类型的能力。了解成年干细胞的调节是一个非常活跃的研究领域，使用干细胞治疗损伤或疾病的可能性代表了新的“再生医学”概念的基础。例如，与哺乳动物一样，肠道上皮中的旧或受损的分化细胞不断脱落和丢失，这些细胞的替代取决于整个肠道上皮的肠道干细胞群（ISC）的活性。有趣的是，许多基因和机制调节ISC在果蝇和哺乳动物之间保守。使用果蝇的研究具有多个优点，包括强大而复杂的遗传技术，这些工具现在可以应用于有关干细胞功能和行为的基本问题。 EB分化发生没有进一步的细胞分裂，EB可以成为吸收性肠细胞（ECS）或秘密肠内分泌细胞（EES）。我的NSERC资助研究涉及研究基因事后编码的C2H2型锌指转录因子的功能。最近，我们发现，事后见识在所有中肠细胞类型中表达。但是，与分化的EC相比，ISC，EB和EES与较低的事后视野有关。此外，我们发现RNAi介导的事后部署的部署导致所有ISC的丧失，而且，令人惊讶的是，增加后观察水平既需要且足够足够的EC差异化。例如，为什么ISC维护需要事后看？ ISC“丢失”会发生什么？事后看来在成熟的分化EC中的功能是什么？除了解决这些问题之外，我们还提出了实验，以更好地了解事后观察的功能，这是人类RAS响应元素结合蛋白-1（RREB-1）的果蝇同源物。有证据表明，事后看来是通过辐射化修改的，我们建议研究如何受到这种修饰影响后观察功能。 RREB-1在胰腺，甲状腺和结肠癌中浸渍了，其在果蝇中的同源物的基础研究不仅会促进对人类RREB-1功能的理解，而且最终可能有助于开发用于治疗这些形式的癌症的新方法。 **