Intrinsic elasticity of nucleosomes is encoded by histone variants and calibrated by their binding partners

作者：Daniël P. Melters, Mary Pitman, Tatini Rakshit, Emilios K. Dimitriadis, Minh Bui, Garegin A. Papoian, Yamini Dalal · 发表于：Proceedings of the National Academy of Sciences · 年份：2019 · DOI：10.1073/pnas.1911880116 · 被引用次数：67 · 研究领域：Genomics and Chromatin Dynamics、RNA and protein synthesis mechanisms、RNA Research and Splicing

Histone variants fine-tune transcription, replication, DNA damage repair, and faithful chromosome segregation. Whether and how nucleosome variants encode unique mechanical properties to their cognate chromatin structures remains elusive. Here, using in silico and in vitro nanoindentation methods, extending to in vivo dissections, we report that histone variant nucleosomes are intrinsically more elastic than their canonical counterparts. Furthermore, binding proteins, which discriminate between histone variant nucleosomes, suppress this innate elasticity and also compact chromatin. Interestingly, when we overexpress the binding proteins in vivo, we also observe increased compaction of chromatin enriched for histone variant nucleosomes, correlating with diminished access. Taken together, these data suggest a plausible link between innate mechanical properties possessed by histone variant nucleosomes, the adaptability of chromatin states in vivo, and the epigenetic plasticity of the underlying locus.