PDF(Pubmed)
Abstract：
The nuclear lamina is a complex network of nuclear lamins and lamin-associated nuclear membrane proteins, which scaffold the nucleus to maintain structural integrity. In Arabidopsis thaliana, nuclear matrix constituent proteins (NMCPs) are essential components of the nuclear lamina and are required to maintain the structural integrity of the nucleus and specific perinuclear chromatin anchoring. At the nuclear periphery, suppressed chromatin overlapping with repetitive sequences and inactive protein-coding genes are enriched. At a chromosomal level, plant chromatin organization in interphase nuclei is flexible and responds to various developmental cues and environmental stimuli. On the basis of these observations in Arabidopsis, and given the role of NMCP genes (CRWN1 and CRWN4) in organizing chromatin positioning at the nuclear periphery, one can expect considerable changes in chromatin-nuclear lamina interactions when the global chromatin organization patterns are being altered in plants. Here we report the highly flexible nature of the plant nuclear lamina, which disassembles substantially under various stress conditions. Focusing on heat stress, we reveal that chromatin domains, initially tethered to the nuclear envelope, remain largely associated with CRWN1 and become scattered in the inner nuclear space. By investigating the three-dimensional chromatin contact network, we further reveal that CRWN1 proteins play a structural role in shaping the changes in genome folding under heat stress. Also, CRWN1 acts as a negative transcriptional coregulator to modulate the shift of the plant transcriptome profile in response to heat stress.
摘要：
核层是核层蛋白和层蛋白相关核膜蛋白的复杂网络，它支撑细胞核以保持结构完整性。在拟南芥中，核基质组成蛋白（NMCP）是核层的重要组成部分，是维持核结构完整性和特定核周染色质锚定所必需的。在核外围，与重复序列和非活性蛋白编码基因重叠的抑制染色质富集。在染色体水平，间期核中的植物染色质组织是灵活的，并响应各种发育线索和环境刺激。根据拟南芥的这些观察结果，考虑到NMCP基因（CRWN1和CRWN4）在核外组织染色质定位中的作用，当全球染色质组织模式在植物中改变时，可以预期染色质-核层相互作用会发生相当大的变化。在这里，我们报告了植物核层的高度柔性，在各种应力条件下分解。专注于热应力，我们发现染色质结构域，最初拴在核外壳上，在很大程度上仍然与CRWN1相关，并分散在内部核空间中。通过研究三维染色质接触网络，我们进一步揭示了CRWN1蛋白在热应激下形成基因组折叠变化的结构作用。此外，CRWN1充当负转录共调节因子，以调节植物转录组谱的变化，以响应热胁迫。
