1
|
Yang Y, Sheng Y, Zheng J, Ma A, Chen S, Lin J, Yang X, Liang Y, Zhang Y, Zheng X. Upregulation of ESPL1 is associated with poor prognostic outcomes in endometrial cancer. Biomarkers 2024; 29:185-193. [PMID: 38568742 DOI: 10.1080/1354750x.2024.2339288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/01/2024] [Indexed: 04/12/2024]
Abstract
BACKGROUND Extra spindle pole bodies-like 1 (ESPL1) is known to play a crucial role in the segregation of sister chromatids during mitosis. Overexpression of ESPL1 is considered to have oncogenic effects in various human cancers. However, the specific biological function of ESPL1 in endometrial cancer (EC) remains unclear. METHODS The TCGA and GEO databases were utilized to assess the expression of ESPL1 in EC. Immunohistochemistry was utilized to detect separase expression in EC samples. Kaplan-Meier survival analysis and Cox regression analysis were performed to evaluate the diagnostic and prognostic significance of ESPL1 in EC. Gene Set Enrichment Analysis (GSEA) was employed to explore the potential signaling pathway of ESPL1 in EC. Cell proliferation and colony formation ability were analyzed using CCK-8 and colony formation assay. RESULTS Our analysis revealed that ESPL1 is significantly upregulated in EC, and its overexpression is associated with advanced clinical characteristics and unfavourable prognostic outcomes. Suppression of ESPL1 attenuated proliferation of EC cell line. CONCLUSION The upregulation of ESPL1 is associated with advanced disease and poor prognosis in EC patients. These findings suggest that ESPL1 has the potential to serve as a diagnostic and prognostic biomarker in EC, highlighting its significance in the management of EC patients.
Collapse
Affiliation(s)
- Yuzhong Yang
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Ying Sheng
- Department of Obstetrics, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Jinhua Zheng
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Aiyu Ma
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Shaohua Chen
- Department of Breast and Thyroid Surgery, Liuzhou People's Hospital Affiliated to Guangxi Medical University, Liuzhou, Guangxi, China
| | - Jing Lin
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Xiaozhen Yang
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Yuanna Liang
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Yan Zhang
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Xiang Zheng
- Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| |
Collapse
|
2
|
Athwal H, Kochiyanil A, Bhat V, Allan AL, Parsyan A. Centrosomes and associated proteins in pathogenesis and treatment of breast cancer. Front Oncol 2024; 14:1370565. [PMID: 38606093 PMCID: PMC11007099 DOI: 10.3389/fonc.2024.1370565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/04/2024] [Indexed: 04/13/2024] Open
Abstract
Breast cancer is the most prevalent malignancy among women worldwide. Despite significant advances in treatment, it remains one of the leading causes of female mortality. The inability to effectively treat advanced and/or treatment-resistant breast cancer demonstrates the need to develop novel treatment strategies and targeted therapies. Centrosomes and their associated proteins have been shown to play key roles in the pathogenesis of breast cancer and thus represent promising targets for drug and biomarker development. Centrosomes are fundamental cellular structures in the mammalian cell that are responsible for error-free execution of cell division. Centrosome amplification and aberrant expression of its associated proteins such as Polo-like kinases (PLKs), Aurora kinases (AURKs) and Cyclin-dependent kinases (CDKs) have been observed in various cancers, including breast cancer. These aberrations in breast cancer are thought to cause improper chromosomal segregation during mitosis, leading to chromosomal instability and uncontrolled cell division, allowing cancer cells to acquire new genetic changes that result in evasion of cell death and the promotion of tumor formation. Various chemical compounds developed against PLKs and AURKs have shown meaningful antitumorigenic effects in breast cancer cells in vitro and in vivo. The mechanism of action of these inhibitors is likely related to exacerbation of numerical genomic instability, such as aneuploidy or polyploidy. Furthermore, growing evidence demonstrates enhanced antitumorigenic effects when inhibitors specific to centrosome-associated proteins are used in combination with either radiation or chemotherapy drugs in breast cancer. This review focuses on the current knowledge regarding the roles of centrosome and centrosome-associated proteins in breast cancer pathogenesis and their utility as novel targets for breast cancer treatment.
Collapse
Affiliation(s)
- Harjot Athwal
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Arpitha Kochiyanil
- Faculty of Science, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Vasudeva Bhat
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- London Regional Cancer Program, London Health Sciences Centre, Lawson Health Research Institute, London, ON, Canada
| | - Alison L. Allan
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- London Regional Cancer Program, London Health Sciences Centre, Lawson Health Research Institute, London, ON, Canada
- Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Armen Parsyan
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- London Regional Cancer Program, London Health Sciences Centre, Lawson Health Research Institute, London, ON, Canada
- Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Division of General Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Surgery, St. Joseph’s Health Care London and London Health Sciences Centre, London, ON, Canada
| |
Collapse
|
3
|
Zhang B, Chen Y, Chen X, Ren Z, Xiang H, Mao L, Zhu G. Genome-wide CRISPR screen identifies ESPL1 limits the response of gastric cancer cells to apatinib. Cancer Cell Int 2024; 24:83. [PMID: 38402402 PMCID: PMC10893712 DOI: 10.1186/s12935-024-03233-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 01/19/2024] [Indexed: 02/26/2024] Open
Abstract
Apatinib was the first anti-angiogenic agent approved for treatment of metastatic gastric cancer (GC). However, the emergence of resistance was inevitable. Thus investigating new and valuable off-target effect of apatinib directly against cancer cells is of great significance. Here, we identified extra spindle pole bodies-like 1 (ESPL1) was responsible for apatinib resistance in GC cells through CRISPR genome-wide gain-of-function screening. Loss of function studies further showed that ESPL1 inhibition suppressed cell proliferation, migration and promoted apoptosis in vitro, and accordingly ESPL1 knockdown sensitized GC cells to apatinib. In addition, we found ESPL1 interacted with mouse double minute 2 (MDM2), a E3 ubiquitin protein ligase, and the combination of MDM2 siRNA with apatinib synergistically ameliorated the resistance induced by ESPL1 overexpression. In summary, our study indicated that ESPL1 played a critical role in apatinib resistance in GC cells. Inhibition of MDM2 could rescue the sensitivity of GC cells to apatinib and reverse ESPL1-mediated resistance.
Collapse
Affiliation(s)
- Bei Zhang
- Institute of Gerontology, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China
- Collaborative Innovation Center for Civil Affairs of Guangzhou, Guangzhou, China
| | - Yan Chen
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xinqi Chen
- Department of Oncology, Affiliated Dongguan Hospital, Southern Medical University, Dongguan, China
| | - Zhiyao Ren
- Institute of Gerontology, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China
- Collaborative Innovation Center for Civil Affairs of Guangzhou, Guangzhou, China
| | - Hong Xiang
- Departments of Oncology, School of Medicine, Guangzhou First People's Hospital, South China University of Technology, Guangzhou, China
| | - Lipeng Mao
- Department of Systems Biomedical Sciences, School of Medicine, Jinan University, Guangzhou, China
| | - Guodong Zhu
- Institute of Gerontology, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China.
- State Key Laboratory of Respiratory Disease, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China.
- Collaborative Innovation Center for Civil Affairs of Guangzhou, Guangzhou, China.
| |
Collapse
|
4
|
Toyoda JH, Martino J, Speer RM, Meaza I, Lu H, Williams AR, Bolt AM, Kouokam JC, Aboueissa AEM, Wise JP. Hexavalent Chromium Targets Securin to Drive Numerical Chromosome Instability in Human Lung Cells. Int J Mol Sci 2023; 25:256. [PMID: 38203427 PMCID: PMC10778806 DOI: 10.3390/ijms25010256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 01/12/2024] Open
Abstract
Hexavalent chromium [Cr(VI)] is a known human lung carcinogen with widespread exposure in environmental and occupational settings. Despite well-known cancer risks, the molecular mechanisms of Cr(VI)-induced carcinogenesis are not well understood, but a major driver of Cr(VI) carcinogenesis is chromosome instability. Previously, we reported Cr(VI) induced numerical chromosome instability, premature centriole disengagement, centrosome amplification, premature centromere division, and spindle assembly checkpoint bypass. A key regulator of these events is securin, which acts by regulating the cleavage ability of separase. Thus, in this study we investigated securin disruption by Cr(VI) exposure. We exposed human lung cells to a particulate Cr(VI) compound, zinc chromate, for acute (24 h) and prolonged (120 h) time points. We found prolonged Cr(VI) exposure caused marked decrease in securin levels and function. After prolonged exposure at the highest concentration, securin protein levels were decreased to 15.3% of control cells, while securin mRNA quantification was 7.9% relative to control cells. Additionally, loss of securin function led to increased separase activity manifested as enhanced cleavage of separase substrates; separase, kendrin, and SCC1. These data show securin is targeted by prolonged Cr(VI) exposure in human lung cells. Thus, a new mechanistic model for Cr(VI)-induced carcinogenesis emerges with centrosome and centromere disruption as key components of numerical chromosome instability, a key driver in Cr(VI) carcinogenesis.
Collapse
Affiliation(s)
- Jennifer H. Toyoda
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| | - Julieta Martino
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| | - Rachel M. Speer
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| | - Idoia Meaza
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| | - Haiyan Lu
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| | - Aggie R. Williams
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| | - Alicia M. Bolt
- Department of Pharmaceutical Sciences, The University of New Mexico College of Pharmacy, Albuquerque, NM 87131, USA;
| | - Joseph Calvin Kouokam
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| | | | - John Pierce Wise
- Wise Laboratory for Environmental and Genetic Toxicology, University of Louisville, 500 S Preston Street, Building 55A, Room 1422, Louisville, KY 40292, USA (R.M.S.); (H.L.); (J.C.K.)
| |
Collapse
|
5
|
Bozin T, Berdyshev I, Chukhontseva K, Karaseva M, Konarev P, Varizhuk A, Lesovoy D, Arseniev A, Kostrov S, Bocharov E, Demidyuk I. NMR structure of emfourin, a novel protein metalloprotease inhibitor: insights into the mechanism of action. J Biol Chem 2023; 299:104585. [PMID: 36889586 PMCID: PMC10124921 DOI: 10.1016/j.jbc.2023.104585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Emfourin (M4in) is a protein metalloprotease inhibitor recently discovered in the bacterium Serratia proteamaculans and the prototype of a new family of protein protease inhibitors with an unknown mechanism of action. Protealysin-like proteases (PLPs) of the thermolysin family are natural targets of emfourin-like inhibitors (ELIs) widespread in bacteria and known in archaea. The available data indicate the involvement of PLPs in interbacterial interaction as well as bacterial interaction with other organisms and likely in pathogenesis. Arguably, ELIs participate in the regulation of bacterial pathogenesis by controlling PLP activity. Here, we determined the 3D structure of M4in using solution NMR spectroscopy. The obtained structure demonstrated no significant similarity to known protein structures. This structure was used to model the M4in-enzyme complex, and the complex model was verified by small-angle X-ray scattering. Based on our analysis of the model, we propose a molecular mechanism for the inhibitor, which was confirmed by site-directed mutagenesis. We show that two spatially close flexible loop regions are critical for the inhibitor-protease interaction. One region includes aspartic acid forming a coordination bond with catalytic Zn2+ of the enzyme, and the second region carries hydrophobic amino acids interacting with protease substrate binding sites. Such an active site structure corresponds to the noncanonical inhibition mechanism. This is the first demonstration of such a mechanism for protein inhibitors of thermolysin family metalloproteases, which puts forward M4in as a new basis for the development of antibacterial agents relying on selective inhibition of prominent factors of bacterial pathogenesis belonging to this family.
Collapse
Affiliation(s)
- TimurN Bozin
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute," Moscow, Russia; National Research Centre "Kurchatov Institute," Moscow, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - IgorM Berdyshev
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute," Moscow, Russia
| | - KseniaN Chukhontseva
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute," Moscow, Russia
| | - MariaA Karaseva
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute," Moscow, Russia
| | - PetrV Konarev
- Shubnikov Institute of Crystallography of the Federal Scientific Research Centre "Crystallography and Photonics," Russian Academy of Sciences, Moscow, Russia
| | - AnnaM Varizhuk
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | - DmitryM Lesovoy
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - AlexanderS Arseniev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - SergeyV Kostrov
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute," Moscow, Russia
| | - EduardV Bocharov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | - IlyaV Demidyuk
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute," Moscow, Russia.
| |
Collapse
|
6
|
Boukaba A, Wu Q, Liu J, Chen C, Liang J, Li J, Strunnikov A. Mapping separase-mediated cleavage in situ. NAR Genom Bioinform 2022; 4:lqac085. [PMID: 36415827 PMCID: PMC9673495 DOI: 10.1093/nargab/lqac085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/13/2022] [Accepted: 10/25/2022] [Indexed: 11/21/2022] Open
Abstract
Separase is a protease that performs critical functions in the maintenance of genetic homeostasis. Among them, the cleavage of the meiotic cohesin during meiosis is a key step in producing gametes in eukaryotes. However, the exact chromosomal localization of this proteolytic cleavage was not addressed due to the lack of experimental tools. To this end, we developed a method based on monoclonal antibodies capable of recognizing the predicted neo-epitopes produced by separase-mediated proteolysis in the RAD21 and REC8 cohesin subunits. To validate the epigenomic strategy of mapping cohesin proteolysis, anti-RAD21 neo-epitopes antibodies were used in ChIP-On-ChEPseq analysis of human cells undergoing mitotic anaphase. Second, a similar analysis applied for mapping of REC8 cleavage in germline cells in Macaque showed a correlation with a subset of alpha-satellites and other repeats, directly demonstrating that the site-specific mei-cohesin proteolysis hotspots are coincident but not identical with centromeres. The sequences for the corresponding immunoglobulin genes show a convergence of antibodies with close specificity. This approach could be potentially used to investigate cohesin ring opening events in other chromosomal locations, if applied to single cells.
Collapse
Affiliation(s)
- Abdelhalim Boukaba
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Qiongfang Wu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jian Liu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Cheng Chen
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jierong Liang
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jingjing Li
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Alexander V Strunnikov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| |
Collapse
|
7
|
Yam CQX, Lim HH, Surana U. DNA damage checkpoint execution and the rules of its disengagement. Front Cell Dev Biol 2022; 10:1020643. [PMID: 36274841 PMCID: PMC9582513 DOI: 10.3389/fcell.2022.1020643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Chromosomes are susceptible to damage during their duplication and segregation or when exposed to genotoxic stresses. Left uncorrected, these lesions can result in genomic instability, leading to cells’ diminished fitness, unbridled proliferation or death. To prevent such fates, checkpoint controls transiently halt cell cycle progression to allow time for the implementation of corrective measures. Prominent among these is the DNA damage checkpoint which operates at G2/M transition to ensure that cells with damaged chromosomes do not enter the mitotic phase. The execution and maintenance of cell cycle arrest are essential aspects of G2/M checkpoint and have been studied in detail. Equally critical is cells’ ability to switch-off the checkpoint controls after a successful completion of corrective actions and to recommence cell cycle progression. Interestingly, when corrective measures fail, cells can mount an unusual cellular response, termed adaptation, where they escape checkpoint arrest and resume cell cycle progression with damaged chromosomes at the cost of genome instability or even death. Here, we discuss the DNA damage checkpoint, the mitotic networks it inhibits to prevent segregation of damaged chromosomes and the strategies cells employ to quench the checkpoint controls to override the G2/M arrest.
Collapse
Affiliation(s)
| | - Hong Hwa Lim
- A*STAR Singapore Immunology Network, Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Uttam Surana
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Pharmacology, National University of Singapore, Singapore, Singapore
- *Correspondence: Uttam Surana,
| |
Collapse
|
8
|
Warecki B, Sullivan W. The Cell Biology of Heterochromatin. Cells 2022; 11:cells11071247. [PMID: 35406810 PMCID: PMC8997597 DOI: 10.3390/cells11071247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/30/2021] [Accepted: 01/04/2022] [Indexed: 12/10/2022] Open
Abstract
A conserved feature of virtually all higher eukaryotes is that the centromeres are embedded in heterochromatin. Here we provide evidence that this tight association between pericentric heterochromatin and the centromere is essential for proper metaphase exit and progression into telophase. Analysis of chromosome rearrangements that separate pericentric heterochromatin and centromeres indicates that they must remain associated in order to balance Cohesin/DNA catenation-based binding forces and centromere-based pulling forces during the metaphase–anaphase transition. In addition, a centromere embedded in heterochromatin facilitates nuclear envelope assembly around the entire complement of segregating chromosomes. Because the nuclear envelope initially forms on pericentric heterochromatin, nuclear envelope formation proceeds from the pole, thus providing time for incorporation of lagging and trailing chromosome arms into the newly formed nucleus. Additional analysis of noncanonical mitoses provides further insights into the functional significance of the tight association between heterochromatin and centromeres.
Collapse
|