@article{12880, abstract = {Peripheral heterochromatin positioning depends on nuclear envelope associated proteins and repressive histone modifications. Here we show that overexpression (OE) of Lamin B1 (LmnB1) leads to the redistribution of peripheral heterochromatin into heterochromatic foci within the nucleoplasm. These changes represent a perturbation of heterochromatin binding at the nuclear periphery (NP) through a mechanism independent from altering other heterochromatin anchors or histone post-translational modifications. We further show that LmnB1 OE alters gene expression. These changes do not correlate with different levels of H3K9me3, but a significant number of the misregulated genes were likely mislocalized away from the NP upon LmnB1 OE. We also observed an enrichment of developmental processes amongst the upregulated genes. ~74% of these genes were normally repressed in our cell type, suggesting that LmnB1 OE promotes gene de-repression. This demonstrates a broader consequence of LmnB1 OE on cell fate, and highlights the importance of maintaining proper levels of LmnB1.}, author = {Kaneshiro, Jeanae M. and Capitanio, Juliana S. and Hetzer, Martin W}, issn = {1949-1042}, journal = {Nucleus}, number = {1}, publisher = {Taylor & Francis}, title = {{Lamin B1 overexpression alters chromatin organization and gene expression}}, doi = {10.1080/19491034.2023.2202548}, volume = {14}, year = {2023}, } @article{14315, abstract = {During apoptosis, caspases degrade 8 out of ~30 nucleoporins to irreversibly demolish the nuclear pore complex. However, for poorly understood reasons, caspases are also activated during cell differentiation. Here, we show that sublethal activation of caspases during myogenesis results in the transient proteolysis of four peripheral Nups and one transmembrane Nup. ‘Trimmed’ NPCs become nuclear export-defective, and we identified in an unbiased manner several classes of cytoplasmic, plasma membrane, and mitochondrial proteins that rapidly accumulate in the nucleus. NPC trimming by non-apoptotic caspases was also observed in neurogenesis and endoplasmic reticulum stress. Our results suggest that caspases can reversibly modulate nuclear transport activity, which allows them to function as agents of cell differentiation and adaptation at sublethal levels.}, author = {Cho, Ukrae H. and Hetzer, Martin W}, issn = {2050-084X}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{Caspase-mediated nuclear pore complex trimming in cell differentiation and endoplasmic reticulum stress}}, doi = {10.7554/eLife.89066}, volume = {12}, year = {2023}, }