Bilateral BBSRC-SFI: Understanding the impact of divergent Sin3A/HDAC1 complex assemblies in gene regulation

双边 BBSRC-SFI：了解不同的 Sin3A/HDAC1 复合体组装对基因调控的影响

• 批准号: BB/P021689/1
• 负责人: Shaun Cowley
• 金额: $ 51.84万
• 依托单位: University of Leicester
• 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%2FP021689%2F1
• 关键词: Bilateral; BBSRC; SFI; Understanding; impact; Bilateral; BBSRC; SFI; Understanding; impact

'Histone deacetylase' (HDAC) enzymes, the class of enzymes which catalyse the removal of the acetyl group from acetylated lysines, have been implicated in almost all cellular processes, including cell cycle, DNA synthesis, DNA repair and gene expression. There are 18 HDACs in mammals, which can be categorized initially as having either a Zn2+-dependent (Class I, II and IV) or NAD+ dependent (Class III - Sirtuins) catalytic domain; and then further by the presence of additional N-terminal domains and a tissue specific expression pattern (Class II and IV) or a short C-terminal tail and ubiquitous expression (Class I). Classically, class I HDACs (HDAC1, 2 and 3) are thought to be involved in the process of gene repression as the catalytic core of canonical co-repressor complexes, such as Sin3A, NuRD and CoREST. The Sin3a complex is thought to be recruited to chromatin by a combination of transcription factors and Sin3-associated proteins (SAPs) where it then mediates histone deacetylation and consequent chromatin compaction. Clinically, generic HDAC inhibitors (HDACi) are used to treat both depression (Valproic acid) and subcutaneous T-cell lymphoma (SAHA). Despite this clinical importance, almost nothing is known about their mode of action. Furthermore, the use of these generic HDACi, is associated with a number of debilitating side-effects including, fatigue, diarrhoea, low platelet counts (thrombocytopaenia), and hyperammonemia, which can lead to brain damage. Therefore, given the positive therapeutic value of HDAC inhibition in numerous disease states, and the appalling side-effects of generic HDACi, the logical way forward is to disrupt individual HDAC complexes. The Sin3A/HDAC1 complex for instance, has been shown to play a critical role in cell cycle regulation, therefore inhibition of additional HDAC1/2 complexes (NuRD, CoREST and MiDAC) may be unnecessary to arrest the growth of cancer cells. A key challenge to specifically inhibiting individual HDAC complexes will be to understand how they are assembled, and which co-factors are essential for their function. To date, most major proteomics studies of the Sin3A complex in mammals have used cancer cell lines. In this proposal, we aim to identify all essential co-factors and substrates (including non-histones) of the Sin3A complex in an array of primary cell types. To achieve this, we will employ state of the art proteomic and transcriptomic approaches, developed in the Cowley and Bracken labs. The specific aims we will pursue are the following: i) assess the requirement for the stem cell specific SAPs, Fam60a and Tet1, to the function of Sin3A in cells, ii) test whether the composition of Sin3A is the same in different types of primary cells, and iii) ask what fraction of the aceytlome (around 4,000 site of Lys-ac in most cell types) is regulated specifically by the Sin3A complex. By using Sin3A as an exemplar of a class I HDAC complex, we expect to extend our understanding of HDAC complexes in a cellular context. By understanding the molecular basis for how HDAC complexes function we can use that knowledge to design new drugs to treat a variety of diseases including, epilepsy, bipolar disorder, Alzheimer's disease, and cancer.

“组蛋白脱乙酰基酶”（HDAC）酶是催化从乙酰化赖氨酸中去除乙酰基的酶类，几乎与所有细胞过程有关，包括细胞周期，DNA合成，DNA，DNA修复和基因表达。哺乳动物中有18个HDAC，最初可以将其归类为具有Zn2+依赖性（I类，II和IV类）或NAD+依赖性（III -sirtuins类）催化域；然后通过存在其他N末端结构域以及组织特异性表达模式（II和IV类）或短C末端尾巴和无处不在的表达（I类）。通常，I类HDAC（HDAC1、2和3）被认为与基因抑制过程有关，作为规范共抑制复合物的催化核心，例如SIN3A，NURD和COREST。 SIN3A复合物被认为是通过转录因子和与SIN3相关蛋白（SAPS）的组合募集到染色质的，然后介导组蛋白脱乙酰基化和随之而来的染色质压实。在临床上，通用HDAC抑制剂（HDACI）用于治疗抑郁症（丙戊酸）和皮下T细胞淋巴瘤（SAHA）。尽管具有这种临床重要性，但几乎一无所知。此外，这些通用HDACI的使用与许多使人衰弱的副作用有关，包括疲劳，腹泻，低血小板计数（血小板细胞增多症）和高度血症，这会导致脑损伤。因此，鉴于HDAC抑制在许多疾病状态的正治疗值以及通用HDACI的令人震惊的副作用，前进的逻辑方法是破坏单个HDAC复合物。例如，SIN3A/HDAC1复合物已被证明在细胞周期调节中起着至关重要的作用，因此抑制其他HDAC1/2复合物（NURD，COREST和MIDAC）可能不需要阻止癌细胞的生长。专门抑制单个HDAC复合物的主要挑战将是了解它们的组装方式，哪些共同因素对于其功能至关重要。迄今为止，哺乳动物中SIN3A复合物的大多数主要蛋白质组学研究都使用了癌细胞系。在此提案中，我们旨在确定一系列主要细胞类型中SIN3A复合物的所有必需的共同因素和底物（包括非晶体）。为了实现这一目标，我们将采用在Cowley和Bracken Labs中开发的最先进的蛋白质组学和转录方法。我们要追求的具体目的是：i）评估对干细胞特异性SAPS，FAM60A和TET1的需求，即Sin3a在细胞中的功能，ii）ii）测试SIN3A的组成在不同类型的原代细胞中是否相同，以及III类型的III iii），询问大多数小区的组合（在大多数小区类型中）在SIN3中询问lys-Ac的4,000个位点。通过将SIN3A作为I类HDAC复合物的示例，我们希望在细胞环境中扩展对HDAC复合物的理解。通过了解HDAC复合物如何功能的分子基础，我们可以使用这些知识来设计新药来治疗各种疾病，包括癫痫，躁郁症，阿尔茨海默氏病和癌症。