German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
Department of Cancer Biology, UCL Cancer Institute, London, UK.
Nat Cell Biol. 2021 Dec;23(12):1224-1239. doi: 10.1038/s41556-021-00774-y. Epub 2021 Dec 7.
Defective silencing of retrotransposable elements has been linked to inflammageing, cancer and autoimmune diseases. However, the underlying mechanisms are only partially understood. Here we implicate the histone H3.3 chaperone Daxx, a retrotransposable element repressor inactivated in myeloid leukaemia and other neoplasms, in protection from inflammatory disease. Loss of Daxx alters the chromatin landscape, H3.3 distribution and histone marks of haematopoietic progenitors, leading to engagement of a Pu.1-dependent transcriptional programme for myelopoiesis at the expense of B-cell differentiation. This causes neutrophilia and inflammation, predisposing mice to develop an autoinflammatory skin disease. While these molecular and phenotypic perturbations are in part reverted in animals lacking both Pu.1 and Daxx, haematopoietic progenitors in these mice show unique chromatin and transcriptome alterations, suggesting an interaction between these two pathways. Overall, our findings implicate retrotransposable element silencing in haematopoiesis and suggest a cross-talk between the H3.3 loading machinery and the pioneer transcription factor Pu.1.
逆转录转座子的沉默缺陷与炎症、癌症和自身免疫性疾病有关。然而,其潜在机制尚不完全清楚。在这里,我们将组蛋白 H3.3 伴侣 Daxx 牵连进来,Daxx 是一种在髓性白血病和其他肿瘤中失活的逆转录转座子抑制剂,它可以保护免受炎症性疾病的侵害。Daxx 的缺失会改变造血祖细胞的染色质景观、H3.3 分布和组蛋白标记,导致 Pu.1 依赖性的髓系细胞生成转录程序的激活,而牺牲了 B 细胞分化。这会导致嗜中性粒细胞增多和炎症,使小鼠易患自身炎症性皮肤病。虽然在同时缺乏 Pu.1 和 Daxx 的动物中,这些分子和表型的改变在一定程度上得到了逆转,但这些小鼠的造血祖细胞表现出独特的染色质和转录组改变,这表明这两种途径之间存在相互作用。总的来说,我们的研究结果表明逆转录转座子沉默在造血中起作用,并提示 H3.3 加载机制与先驱转录因子 Pu.1 之间存在相互作用。