How heterochromatin composition impacts architecture

在不同的组织中，细胞核中存在相同的遗传信息，但其表达和组织方式不同。这在很大程度上不是在DNA序列本身的水平上控制，而是在表观遗传水平上控制。这种表观遗传调控取决于几个因素，包括DNA甲基化和与核蛋白的相互作用。一个重要的调控机制是将DNA组织成主动转录的常染色质和浓缩的，大多数是“沉默的”异染色质。异染色质的结构、组成和形成尚不完全清楚，但已知它们在组织之间存在差异，这可能有助于并反映在不同细胞类型中发现的不同蛋白质组。异染色质组织的一个重要方面是导致所谓的色中心形成的大规模聚集。MeCP2蛋白与甲基化DNA相互作用，已知参与色中心形成，但其作用尚未完全了解。这种X染色体相关基因的突变对人类健康很重要，因为它们与子宫内致死（男性）或神经（女性）表型有关。这种病理背后的分子机制尚不清楚。我们的项目汇集了在细胞生物学、表观遗传学、显微镜学、蛋白质组学和结构生物学方面有着强大记录的研究人员。利用我们的综合专业知识和基础设施，我们将研究来自不同细胞和组织类型的异染色质的结构和分子组成，特别关注从亚细胞到分子尺度的不同MeCP2突变体的结构和相互作用。我们将通过协同使用一系列技术来实现这一目标，包括（荧光）显微镜和图像分析、蛋白质生物化学、基于质谱的蛋白质组学和构象敏感质谱。

In different tissues, the same genetic information is present in the cell nucleus but its expression and organization differs. This is largely controlled not at the level of the DNA sequence per se but at the epigenetic level. This epigenetic regulation depends on several factors, including DNA methylation and interaction with nuclear proteins. One important regulatory mechanism is the organization of DNA into actively transcribed euchromatin and condensed, mostly ‘silent’ heterochromatin. The structure, composition, and formation of heterochromatin are not fully understood, but they are known to differ between tissues, and this likely contributes to and reflects the different proteomes found in different cell types. An important aspect of heterochromatin organization is the large-scale clustering that leads to the formation of so-called chromocenters. The protein MeCP2 interacts with methylated DNA and is known to be involved in chromocenter formation, but its role is not fully understood. Mutations in this X chromosome-linked gene are important to human health, as they are associated with in utero lethal (males) or neurological (females) phenotypes. The molecular mechanism behind this pathology is not well understood. Our project brings together researchers with strong track records in cell biology, epigenetics, microscopy, proteomics, and structural biology. Using our combined expertise and infrastructure, we will investigate the structure and molecular composition of heterochromatin from different cell and tissue types, with particular attention to the structure and interactions of different MeCP2 mutants from the subcellular to the molecular scale. We will achieve this through the synergistic use of a range of techniques, including (fluorescence) microscopy and image analysis, protein biochemistry, mass spectrometry-based proteomics, and conformation-sensitive mass spectrometry.