Understanding the essential requirement for HDAC1 and HDAC2 in tissue development and homeostasis: implications for disease and therapy.

‘组蛋白脱乙酰酶’(HDAC)酶存在于人体的所有细胞中。它们的功能是关闭基因，并确保它们保持关闭状态。我的实验室研究HDAC是如何做到这一点的，以及在每个细胞的25,000个基因中，哪些基因被选中进行失活。HDAC酶也代表着一个令人兴奋的医学机会，因为它们是“可下药的”。抑制HDAC活性的药物已经作为抗癌药物在临床上使用，并因其对痴呆症和抗炎特性的有益作用而进一步开发。因此，研究它们的生理作用既有令人信服的应用动机，也有学术动机。为了评估它们作为药理靶点的潜力，我们需要更好地了解单个HDAC酶在正常细胞中是如何发挥作用的。在这项研究中，我们打算研究两种密切相关的HDAC酶，HDAC1和HDAC2。了解酶如何工作的最好方法之一是产生突变细胞，在这些突变细胞中，特定的酶已经失活，或被“敲除”。然后，可以检查这些“敲除”细胞的特征变化，例如，缺乏生长，这可以归因于特定酶的功能。以前，我们只为HDAC1和HDAC2产生了“敲除”细胞，但它们的功能是重叠的，因此对细胞生长的影响很小。为了解决这一问题，我们生成了可以同时移除HDAC1和HDAC2的细胞，即所谓的“双敲除”细胞。早期的实验表明，失去这两种酶会导致细胞死亡，这表明它们的活性是必不可少的。利用DNA技术，有可能重新添加正常或突变形式的HDAC1，以防止双敲除细胞死亡，然后问，酶的哪些部分对其功能重要？在相关实验中，我们还打算使用一种名为X射线结晶学的技术来可视化HDAC1与一种名为MTA1的分子结合的实际分子结构。HDAC1与细胞内其他分子的相互作用是其功能的基础。通过了解这些相互作用的分子基础，我们可以更好地了解HDAC酶在正常细胞和癌细胞中的工作原理，并有可能利用这一知识设计新药以防止它们发挥作用。在我们的双基因敲除细胞中可以看到，阻止HDAC1和HDAC2工作的能力会导致细胞停止生长和死亡，使它们成为寻找改进的抗癌药物的极佳药物靶点。

'Histone deacetylase' (HDAC) enzymes are present in all cells of the body. Their function is to switch genes 'off', and make sure they stay 'off'. My lab studies how HDACs do this and which, amongst the 25,000 genes in each cell, are selected for inactivation. HDAC enzymes also represent an exciting medical opportunity because they are 'druggable'. Already, drugs which inhibit HDAC activity are being used in the clinic as anti-cancer agents, and are being further developed for their beneficial effects on dementia and anti-inflammatory properties. There is therefore a compelling applied, as well as academic motivation for studying their physiological roles. In order to assess their potential as pharmacological targets, we need an improved understanding of how individual HDAC enzymes work in normal cells. In this study we intend study two closely related HDAC enzymes, HDAC1 and HDAC2. One of the best methods for understanding how an enzyme works is to generate mutant cells in which the specific enzyme has been inactivated, or 'knocked-out'. These 'knock-out' cells can then be examined for changes in their characteristics, lack of growth for instance, which can then be attributed to the function of that particular enzyme. Previously, we have generated 'knock-out' cells for HDAC1 and HDAC2 alone, but their function is overlapping, and so the effects on cell growth were small. To get around this, we have generated cells in which HDAC1 and 2 can be removed at the same time, so called 'double knock-out' cells. Early experiments indicate that loss of both enzymes causes cells to die, indicating that their activity is essential. Using DNA technology it is possible to add back normal or mutated forms of HDAC1 to prevent the double knock-out cells from dying and then ask, which parts of the enzyme are important for its function? In related experiments, we also intend to visualize the actual molecular structure of HDAC1 bound to a molecule called MTA1, using a technique called X-ray crystallography. The interaction of HDAC1 with other molecules in the cell is fundamental to their function. By understanding the molecular basis of these interactions we can better understand how HDAC enzymes work in normal and cancer cells, and potentially use that knowledge to design new drugs to prevent them from working. The ability to stop HDAC1 and 2 from working, as seen in our double knock-out cells, causes cells to stop growing and die, making them excellent drug targets in the search for improved anti-cancer agents.