Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary.
Nat Commun. 2024 Oct 24;15(1):9171. doi: 10.1038/s41467-024-53514-9.
H2A.Z-nucleosomes are present in both euchromatin and heterochromatin and it has proven difficult to interpret their disparate roles in the context of their stability features. Using an in situ assay of nucleosome stability and DT40 cells expressing engineered forms of the histone variant we show that native H2A.Z, but not C-terminally truncated H2A.Z (H2A.Z∆C), is released from nucleosomes of peripheral heterochromatin at unusually high salt concentrations. H2A.Z and H3K9me3 landscapes are reorganized in H2A.Z∆C-nuclei and overall sensitivity of chromatin to nucleases is increased. These tail-dependent differences are recapitulated upon treatment of HeLa nuclei with the H2A.Z-tail-peptide (C9), with MNase sensitivity being increased genome-wide. Fluorescence correlation spectroscopy revealed C9 binding to reconstituted nucleosomes. When introduced into live cells, C9 elicited chromatin reorganization, overall nucleosome destabilization and changes in gene expression. Thus, H2A.Z-nucleosomes influence global chromatin architecture in a tail-dependent manner, what can be modulated by introducing the tail-peptide into live cells.
H2A.Z-核小体存在于常染色质和异染色质中，其在稳定性特征背景下的不同作用很难解释。本研究使用核小体稳定性的原位测定和表达工程化组蛋白变体的 DT40 细胞，表明天然 H2A.Z，但不是 C 端截断的 H2A.Z（H2A.Z∆C），可以在异常高的盐浓度下从周边异染色质的核小体中释放。H2A.Z 和 H3K9me3 景观在 H2A.Z∆C-核小体中重新组织，并且染色质对核酸酶的整体敏感性增加。在用 H2A.Z-尾部肽（C9）处理 HeLa 核时，这些尾部依赖性差异得到了重现，MNase 敏感性在全基因组范围内增加。荧光相关光谱法显示 C9 与重组成核小体结合。当引入活细胞时，C9 引起染色质重排、整体核小体不稳定和基因表达变化。因此，H2A.Z-核小体以依赖尾部的方式影响全局染色质结构，通过将尾部肽引入活细胞可以调节这种结构。
