Histone H1s or the linker histones are a family of dynamic chromatin compacting proteins that are essential for higher-order chromatin organization. These highly positively charged proteins were previously thought to function solely as repressors of transcription. However, over the last decade, there is a growing interest in understanding this multi-protein family, finding that not all variants act as repressors. Indeed, the H1 family members appear to have distinct affinities for chromatin and may potentially affect distinct functions. This would suggest a more nuanced contribution of H1 to chromatin organization. The advent of new technologies to probe H1 dynamics in vivo, combined with powerful computational biology, and in vitro imaging tools have greatly enhanced our knowledge of the mechanisms by which H1 interacts with chromatin. This family of proteins can be metaphorically compared to the Golden Snitch from the Harry Potter series, buzzing on and off several regions of the chromatin, in combat with competing transcription factors and chromatin remodellers, thereby critical to the epigenetic endgame on short and long temporal scales in the life of the nucleus. Here, we summarize recent efforts spanning structural, computational, genomic and genetic experiments which examine the linker histone as an unseen architect of chromatin fibre in normal and diseased cells and explore unanswered fundamental questions in the field.

组蛋白 H1 或接头组蛋白是一个动态染色质压缩蛋白家族，对于高级染色质组织至关重要。这些带高正电荷的蛋白质以前被认为仅作为转录抑制因子起作用。然而，在过去十年中，人们对了解这个多蛋白家族的兴趣日益浓厚，发现并非所有变体都充当阻遏物。事实上，H1 家族成员似乎对染色质具有不同的亲和力，并可能影响不同的功能。这表明 H1 对染色质组织的贡献更为细微。探索体内H1 动力学的新技术的出现，结合强大的计算生物学和体外成像工具极大地增强了我们对 H1 与染色质相互作用机制的认识。这个蛋白质家族可以比喻为哈利波特系列中的金色飞贼，在染色质的几个区域上下嗡嗡作响，与竞争的转录因子和染色质重塑者作战，因此对短期和长期时间尺度上的表观遗传残局至关重要在原子核的生命中。在这里，我们总结了最近在结构、计算、基因组和遗传实验方面所做的努力，这些实验检查了接头组蛋白作为正常和患病细胞中染色质纤维的隐形结构，并探索了该领域未解决的基本问题。