Katharina S Keuenhof, Verena Kohler, Filomena Broeskamp, Dimitra Panagaki, Sean D Speese, Sabrina Büttner, Johanna L Höög
{"title":"Nuclear envelope budding and its cellular functions.","authors":"Katharina S Keuenhof, Verena Kohler, Filomena Broeskamp, Dimitra Panagaki, Sean D Speese, Sabrina Büttner, Johanna L Höög","doi":"10.1080/19491034.2023.2178184","DOIUrl":"10.1080/19491034.2023.2178184","url":null,"abstract":"<p><p>The nuclear pore complex (NPC) has long been assumed to be the sole route across the nuclear envelope, and under normal homeostatic conditions it is indeed the main mechanism of nucleo-cytoplasmic transport. However, it has also been known that e.g. herpesviruses cross the nuclear envelope utilizing a pathway entitled nuclear egress or envelopment/de-envelopment. Despite this, a thread of observations suggests that mechanisms similar to viral egress may be transiently used also in healthy cells. It has since been proposed that mechanisms like nuclear envelope budding (NEB) can facilitate the transport of RNA granules, aggregated proteins, inner nuclear membrane proteins, and mis-assembled NPCs. Herein, we will summarize the known roles of NEB as a physiological and intrinsic cellular feature and highlight the many unanswered questions surrounding these intriguing nuclear events.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":"14 1","pages":"2178184"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9980700/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9371338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"CiRS-7 Enhances the Liquid-liquid Phase Separation of miRISC and Promotes DNA Damage Repair.","authors":"Yun-Long Wang, Li-Li Feng, Jie Shi, Wan-Ying Chen, Shu-Ying Bie, Shao-Mei Bai, Guang-Dong Zeng, Rui-Zhi Wang, Jian Zheng, Xiang-Bo Wan, Xin-Juan Fan","doi":"10.1080/19491034.2023.2293599","DOIUrl":"10.1080/19491034.2023.2293599","url":null,"abstract":"<p><p>Noncoding RNAs have been found to play important roles in DNA damage repair, whereas the participation of circRNA remains undisclosed. Here, we characterized ciRS-7, a circRNA containing over 70 putative miR-7-binding sites, as an enhancer of miRISC condensation and DNA repair. Both <i>in vivo</i> and <i>in vitro</i> experiments confirmed the condensation of TNRC6B and AGO2, two core protein components of human miRISC. Moreover, overexpressing ciRS-7 largely increased the condensate number of TNRC6B and AGO2 in cells, while silencing ciRS-7 reduced it. Additionally, miR-7 overexpression also promoted miRISC condensation. Consistent with the previous report that AGO2 participated in RAD51-mediated DNA damage repair, the overexpression of ciRS-7 significantly promoted irradiation-induced DNA damage repair by enhancing RAD51 recruitment. Our results uncover a new role of circRNA in liquid-liquid phase separation and provide new insight into the regulatory mechanism of ciRS-7 on miRISC function and DNA repair.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":"14 1","pages":"2293599"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10730229/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138813526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nucleus (Austin, Tex.)Pub Date : 2023-12-01Epub Date: 2023-12-05DOI: 10.1080/19491034.2023.2288476
Kamsi O Odinammadu, Khurts Shilagardi, Kelsey Tuminelli, Daniel P Judge, Leslie B Gordon, Susan Michaelis
{"title":"The farnesyl transferase inhibitor (FTI) lonafarnib improves nuclear morphology in ZMPSTE24-deficient fibroblasts from patients with the progeroid disorder MAD-B.","authors":"Kamsi O Odinammadu, Khurts Shilagardi, Kelsey Tuminelli, Daniel P Judge, Leslie B Gordon, Susan Michaelis","doi":"10.1080/19491034.2023.2288476","DOIUrl":"10.1080/19491034.2023.2288476","url":null,"abstract":"<p><p>Several related progeroid disorders are caused by defective post-translational processing of prelamin A, the precursor of the nuclear scaffold protein lamin A, encoded by <i>LMNA</i>. Prelamin A undergoes farnesylation and additional modifications at its C-terminus. Subsequently, the farnesylated C-terminal segment is cleaved off by the zinc metalloprotease ZMPSTE24. The premature aging disorder Hutchinson Gilford progeria syndrome (HGPS) and a related progeroid disease, mandibuloacral dysplasia (MAD-B), are caused by mutations in <i>LMNA</i> and <i>ZMPSTE24</i>, respectively, that result in failure to process the lamin A precursor and accumulate permanently farnesylated forms of prelamin A. The farnesyl transferase inhibitor (FTI) lonafarnib is known to correct the aberrant nuclear morphology of HGPS patient cells and improves lifespan in children with HGPS. Importantly, and in contrast to a previous report, we show here that FTI treatment also improves the aberrant nuclear phenotypes in MAD-B patient cells with mutations in <i>ZMPSTE24</i> (P248L or L425P). As expected, lonafarnib does not correct nuclear defects for cells with lamin A processing-proficient mutations. We also examine prelamin A processing in fibroblasts from two individuals with a prevalent laminopathy mutation <i>LMNA</i>-R644C. Despite the proximity of residue R644 to the prelamin A cleavage site, neither R644C patient cell line shows a prelamin A processing defect, and both have normal nuclear morphology. This work clarifies the prelamin A processing status and role of FTIs in a variety of laminopathy patient cells and supports the FDA-approved indication for the FTI Zokinvy for patients with processing-deficient progeroid laminopathies, but not for patients with processing-proficient laminopathies.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":"14 1","pages":"2288476"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10730222/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138489229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nucleus-wide analysis of coherent RNA pol II movement in the context of chromatin dynamics in living cancer cells.","authors":"Haitham A Shaban","doi":"10.1080/19491034.2022.2157133","DOIUrl":"https://doi.org/10.1080/19491034.2022.2157133","url":null,"abstract":"<p><p>Activation of transcription results in coordinated movement of chromatin over a range of micrometers. To investigate how transcriptional regulation affects the mobility of RNA Pol II molecules and whether this movement response depends on the coordinated movement of chromatin, we used our Dense Flow reConstruction and Correlation (DFCC) method. Using DFCC, we studies the nucleus-wide coherent movements of RNA Pol II in the context of DNA in humancancer cells. This study showed the dependance of coherent movements of RNA Pol II molecules (above 1 µm) on transcriptional activity. Here, we share the dataset of this study, includes nucleus-wide live imaging and analysis of DNA and RNA polymerase II in different transcription states, and the code for teh analysis. Our dataset may provide researchers interested in the long-range organization of chromatin in living cell images with the ability to link the structural genomic compartment to dynamic information. .</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":"13 1","pages":"313-318"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9754109/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10465804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Architectural control of mesenchymal stem cell phenotype through nuclear actin.","authors":"Janet Rubin, Andre J van Wijnen, Gunes Uzer","doi":"10.1080/19491034.2022.2029297","DOIUrl":"10.1080/19491034.2022.2029297","url":null,"abstract":"<p><p>There is growing appreciation that architectural components of the nucleus regulate gene accessibility by altering chromatin organization. While nuclear membrane connector proteins link the mechanosensitive actin cytoskeleton to the nucleoskeleton, actin's contribution to the inner architecture of the nucleus remains enigmatic. Control of actin transport into the nucleus, plus the presence of proteins that control actin structure (the actin tool-box) within the nucleus, suggests that nuclear actin may support biomechanical regulation of gene expression. Cellular actin structure is mechanoresponsive: actin cables generated through forces experienced at the plasma membrane transmit force into the nucleus. We posit that dynamic actin remodeling in response to such biomechanical cues provides a novel level of structural control over the epigenetic landscape. We here propose to bring awareness to the fact that mechanical forces can promote actin transfer into the nucleus and control structural arrangements as illustrated in mesenchymal stem cells, thereby modulating lineage commitment.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":" ","pages":"35-48"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8837231/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39761952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Garrett T Santini, Parisha P Shah, Ashley Karnay, Rajan Jain
{"title":"Aberrant chromatin organization at the nexus of laminopathy disease pathways.","authors":"Garrett T Santini, Parisha P Shah, Ashley Karnay, Rajan Jain","doi":"10.1080/19491034.2022.2153564","DOIUrl":"10.1080/19491034.2022.2153564","url":null,"abstract":"","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":"13 1","pages":"300-312"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9746625/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9614948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cell cycle control of kinetochore assembly.","authors":"Qianhua Dong, Fei Li","doi":"10.1080/19491034.2022.2115246","DOIUrl":"https://doi.org/10.1080/19491034.2022.2115246","url":null,"abstract":"<p><p>The kinetochore is a large proteinaceous structure assembled on the centromeres of chromosomes. The complex machinery links chromosomes to the mitotic spindle and is essential for accurate chromosome segregation during cell division. The kinetochore is composed of two submodules: the inner and outer kinetochore. The inner kinetochore is assembled on centromeric chromatin and persists with centromeres throughout the cell cycle. The outer kinetochore attaches microtubules to the inner kinetochore, and assembles only during mitosis. The review focuses on recent advances in our understanding of the mechanisms governing the proper assembly of the outer kinetochore during mitosis and highlights open questions for future investigation.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":" ","pages":"208-220"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9427032/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33445686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chromatin accessibility: methods, mechanisms, and biological insights.","authors":"Andrés R Mansisidor, Viviana I Risca","doi":"10.1080/19491034.2022.2143106","DOIUrl":"10.1080/19491034.2022.2143106","url":null,"abstract":"<p><p>Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility <i>in vivo</i> include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":"13 1","pages":"236-276"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/06/1f/KNCL_13_2143106.PMC9683059.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10021440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mark Tingey, Yichen Li, Wenlan Yu, Albert Young, Weidong Yang
{"title":"Spelling out the roles of individual nucleoporins in nuclear export of mRNA.","authors":"Mark Tingey, Yichen Li, Wenlan Yu, Albert Young, Weidong Yang","doi":"10.1080/19491034.2022.2076965","DOIUrl":"10.1080/19491034.2022.2076965","url":null,"abstract":"<p><p>The Nuclear Pore Complex (NPC) represents a critical passage through the nuclear envelope for nuclear import and export that impacts nearly every cellular process at some level. Recent technological advances in the form of Auxin Inducible Degron (AID) strategies and Single-Point Edge-Excitation sub-Diffraction (SPEED) microscopy have enabled us to provide new insight into the distinct functions and roles of nuclear basket nucleoporins (Nups) upon nuclear docking and export for mRNAs. In this paper, we provide a review of our recent findings as well as an assessment of new techniques, updated models, and future perspectives in the studies of mRNA's nuclear export.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":"13 1","pages":"170-193"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9132428/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9415494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hui Zhang, Hector Romero, Annika Schmidt, Katalina Gagova, Weihua Qin, Bianca Bertulat, Anne Lehmkuhl, Manuela Milden, Malte Eck, Tobias Meckel, Heinrich Leonhardt, M Cristina Cardoso
{"title":"MeCP2-induced heterochromatin organization is driven by oligomerization-based liquid-liquid phase separation and restricted by DNA methylation.","authors":"Hui Zhang, Hector Romero, Annika Schmidt, Katalina Gagova, Weihua Qin, Bianca Bertulat, Anne Lehmkuhl, Manuela Milden, Malte Eck, Tobias Meckel, Heinrich Leonhardt, M Cristina Cardoso","doi":"10.1080/19491034.2021.2024691","DOIUrl":"https://doi.org/10.1080/19491034.2021.2024691","url":null,"abstract":"<p><p>Heterochromatin is the highly compacted form of chromatin with various condensation levels hallmarked by high DNA methylation. MeCP2 is mostly known as a DNA methylation reader but has also been reported as a heterochromatin organizer. Here, we combine liquid-liquid phase separation (LLPS) analysis and single-molecule tracking with quantification of local MeCP2 concentrations <i>in vitro</i> and <i>in vivo</i> to explore the mechanism of MeCP2-driven heterochromatin organization and dynamics. We show that MeCP2 alone forms liquid-like spherical droplets via multivalent electrostatic interactions and with isotropic mobility. Crowded environments and DNA promote MeCP2 LLPS and slow down MeCP2 mobility. DNA methylation, however, restricts the growth of heterochromatin compartments correlating with immobilization of MeCP2. Furthermore, MeCP2 self-interaction is required for LLPS and is disrupted by Rett syndrome mutations. In summary, we are able to model the heterochromatin compartmentalization as well as MeCP2 concentration and heterogeneous motion in the minimal <i>in vitro</i> system.</p>","PeriodicalId":74323,"journal":{"name":"Nucleus (Austin, Tex.)","volume":" ","pages":"1-34"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/18/0d/KNCL_13_2024691.PMC8855868.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39916427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}