The plant nuclear lamina disassembles to regulate plant genome folding in stress conditions

The nuclear lamina (NL) is a complex network of nuclear lamins and lamin-associated nuclear membrane proteins, which scaffold the nucleus to maintain structural integrity. In <em>Arabidopsis</em> thaliana, Nuclear Matrix Constituent Proteins (NMCPs) are essential components of the NL and are required to maintain the structural integrity of the nucleus and specific perinuclear chromatin anchoring. At a chromosomal level, plant chromatin organization in interphase nuclei displays flexibilities. Many developmental cues and environmental factors, such as dedifferentiation, leaf development, seedling growth, floral transition, seed development, light intensity, microbe infection, and temperature stress, can trigger global rearrangement of chromatin, demonstrating a tight connection between the structural arrangement of chromatin and its activities. Based on these observations from <em>Arabidopsis</em>, and given the role of AtNMCP genes (CRWN1 and CRWN4) in organizing chromatin positioning at the nuclear periphery, one can expect considerable changes in chromatin-NL interactions when the global chromatin organization patterns are being altered in plants. In this study, we show that plant nuclear lamina disassembles substantially under various stress conditions. By focusing on heat stress, we reveal that chromatin domains, initially tethered to the nuclear envelope, remain largely associated with CRWN1 and became scattered in the inner nuclear space. Via investigating the three-dimensional chromatin contact network, we further reveal that CRWN1 proteins play a structural role, shaping changes in genome folding under heat stress. Also, CRWN1 acts as a negative transcriptional co-regulator to modulate the shift of the plant transcriptome profile in response to heat stress. <br> Here files of large datasets associated with this study, such as Hi-C matrices and ChIP-seq track files in 100 bp bin size, and BigWig files, are available for downloading. <br>