Inducible histone K-to-M mutations are dynamic tools to probe the physiological role of site-specific histone methylation in vitro and in vivo
Inducible histone K-to-M mutations are dynamic tools to probe the physiological role of site-specific histone methylation in vitro and in vivo
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DOI：
10.1038/s41556-019-0403-5
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发表时间：
2019-11-01
影响因子：
21.3
通讯作者：
Hochedlinger, Konrad
中科院分区：
文献类型：
--
作者：
Brumbaugh, Justin;Kim, Ik Soo;Hochedlinger, Konrad
发育和分化与组蛋白修饰的深刻变化有关，但其在体内的功能仍不完全清楚。在这里，我们建立了表达诱导组蛋白H3赖氨酸-蛋氨酸（K-to-M）突变体的小鼠模型，该突变体在特定位点抑制甲基化。表达H3K36M的小鼠会出现严重贫血，伴有红细胞生成受阻，出现明显的造血干细胞缺陷，并迅速死亡。相比之下，表达H3K9M的小鼠存活长达一年，并表现出多能祖细胞的扩增、异常的淋巴生成和血小板增多。此外，一些H3K9M小鼠屈服于侵袭性T细胞白血病/淋巴瘤，而H3K36M小鼠在睾丸和肠道中表现出分化缺陷。从机制上讲，诱导任何一种突变都降低了相应的全基因组组蛋白三甲基化模式，改变了染色质可及性以及基因表达景观。引人注目的是，停止转基因表达在很大程度上恢复了分化程序。我们的工作表明，在分化的几个特定阶段需要单独的染色质修饰，并引入了强大的工具来询问它们在体内的作用。
Development and differentiation are associated with profound changes to histone modifications, yet their in vivo function remains incompletely understood. Here, we generated mouse models expressing inducible histone H3 lysine-to-methionine (K-to-M) mutants, which globally inhibit methylation at specific sites. Mice expressing H3K36M developed severe anaemia with arrested erythropoiesis, a marked haematopoietic stem cell defect, and rapid lethality. By contrast, mice expressing H3K9M survived up to a year and showed expansion of multipotent progenitors, aberrant lymphopoiesis and thrombocytosis. Additionally, some H3K9M mice succumbed to aggressive T cell leukaemia/lymphoma, while H3K36M mice exhibited differentiation defects in testis and intestine. Mechanistically, induction of either mutant reduced corresponding histone trimethylation patterns genome-wide and altered chromatin accessibility as well as gene expression landscapes. Strikingly, discontinuation of transgene expression largely restored differentiation programmes. Our work shows that individual chromatin modifications are required at several specific stages of differentiation and introduces powerful tools to interrogate their roles in vivo.