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Current Genetics Oct 2019Exogenous signals induce cells to enter the specialized cell division process of meiosis, which produces haploid gametes from diploid progenitor cells. Once cells... (Review)
Review
Exogenous signals induce cells to enter the specialized cell division process of meiosis, which produces haploid gametes from diploid progenitor cells. Once cells initiate the meiotic divisions, it is imperative that they complete meiosis. Inappropriate exit from meiosis and entrance into mitosis can create polyploid cells and can lead to germline tumors. Saccharomyces cerevisiae cells enter meiosis when starved of nutrients but can return to mitosis if provided nutrient-rich medium before a defined commitment point. Once past the meiotic commitment point in prometaphase I, cells stay committed to meiosis even in the presence of a mitosis-inducing signal. Recent research investigated the maintenance of meiotic commitment in budding yeast and found that two checkpoints that do not normally function in meiosis I, the DNA damage checkpoint and the spindle position checkpoint, have crucial functions in maintaining meiotic commitment. Here, we review these findings and discuss how the mitosis-inducing signal of nutrient-rich medium could activate these two checkpoints in meiosis to prevent inappropriate meiotic exit.
Topics: DNA Damage; Meiosis; Saccharomyces cerevisiae; Spindle Apparatus
PubMed: 31028453
DOI: 10.1007/s00294-019-00981-z -
BMC Medical Genomics Oct 2020NEK2 has an established involvement in hepatocellular carcinoma (HCC) but the roles of NEK2 and its interacting proteins in HCC have not been systematically explored.
BACKGROUND
NEK2 has an established involvement in hepatocellular carcinoma (HCC) but the roles of NEK2 and its interacting proteins in HCC have not been systematically explored.
METHODS
This study examined NEK2 and its interacting proteins in HCC based on multiple databases.
RESULTS
NEK2 mRNA was highly expressed in HCC tissues compared with normal liver tissues. The survival of HCC patients with high NEK2 mRNA expression was shorter than those with low expression. MAD1L1, CEP250, MAPK1, NDC80, PPP1CA, PPP1R2 and NEK11 were the interacting proteins of NEK2. Among them, NDC80 and CEP250 were the key interacting proteins of NEK2. Mitotic prometaphase may be the key pathway that NEK2 and its interacting proteins contributed to HCC pathogenesis. NEK2, NDC80 and CEP250 mRNAs were highly expressed in HCC tissues compared with normal liver tissues. The mRNA levels of NEK2 were positively correlated with those of NDC80 or CEP250. Univariate regression showed that NEK2, NDC80 and CEP250 mRNA expressions were significantly associated with HCC patients' survival. Multivariate regression showed that NDC80 mRNA expression was an independent predictor for HCC patients' survival. Methylations and genetic alterations of NEK2, NDC80 and CEP250 were observed in HCC samples. The alterations of NEK2, NDC80 and CEP250 genes were co-occurrence. Patients with high mRNA expression and genetic alterations of NEK2, NDC80 and CEP250 had poor prognosis.
CONCLUSIONS
NEK2 and its interacting proteins NDC80 and CEP250 play important roles in HCC development and progression and thus may be potentially used as biomarkers and therapeutic targets of HCC.
Topics: Autoantigens; Biomarkers, Tumor; Carcinoma, Hepatocellular; Case-Control Studies; Cell Cycle Proteins; Cytoskeletal Proteins; Female; Follow-Up Studies; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; Male; NIMA-Related Kinases; Prognosis; Protein Interaction Domains and Motifs; Survival Rate
PubMed: 33109182
DOI: 10.1186/s12920-020-00812-y -
Frontiers in Oncology 2022Breast cancer (BRCA) has become the most frequently appearing, lethal, and aggressive cancer with increasing morbidity and mortality. Previously, it was discovered that...
BACKGROUND
Breast cancer (BRCA) has become the most frequently appearing, lethal, and aggressive cancer with increasing morbidity and mortality. Previously, it was discovered that the HAUS5 protein is involved in centrosome integrity, spindle assembly, and the completion of the cytoplasmic division process during mitosis. By encouraging chromosome misdivision and aneuploidy, HAUS5 has the potential to cause cancer. The significance of HAUS5 in BRCA and the relationship between its expression and clinical outcomes or immune infiltration remains unclear.
METHODS
Pan-cancer was analyzed by TIMER2 web and the expression differential of HAUS5 was discovered. The prognostic value of HAUS5 for BRCA was evaluated with KM plotter and confirmed with Gene Expression Omnibus (GEO) dataset. Following that, we looked at the relationship between the high and low expression groups of HAUS5 and breast cancer clinical indications. Signaling pathways linked to HAUS5 expression were discovered using Gene Set Enrichment Analysis (GSEA). The relative immune cell infiltrations of each sample were assessed using the CIBERSORT algorithm and ESTIMATE method. We evaluated the Tumor Mutation Burden (TMB) value between the two sets of samples with high and low HAUS5 expression, as well as the differences in gene mutations between the two groups. The proliferation changes of BRCA cells after knockdown of HAUS5 were evaluated by fluorescence cell counting and colony formation assay.
RESULT
HAUS5 is strongly expressed in most malignancies, and distinct associations exist between HAUS5 and prognosis in BRCA patients. Upregulated HAUS5 was associated with poor clinicopathological characteristics such as tumor T stage, ER, PR, and HER2 status. mitotic prometaphase, primary immunodeficiency, DNA replication, cell cycle related signaling pathways were all enriched in the presence of elevated HAUS5 expression, according to GSEA analysis. The BRCA microenvironment's core gene, HAUS5, was shown to be related with invading immune cell subtypes and tumor cell stemness. TMB in the HAUS5-low expression group was significantly higher than that in the high expression group. The mutation frequency of 15 genes was substantially different in the high expression group compared to the low expression group. BRCA cells' capacity to proliferate was decreased when HAUS5 was knocked down.
CONCLUSION
These findings show that HAUS5 is a positive regulator of BRCA progression that contributes to BRCA cells proliferation. As a result, HAUS5 might be a novel prognostic indicator and therapeutic target for BRCA patients.
PubMed: 35280773
DOI: 10.3389/fonc.2022.829777 -
Current Oncology (Toronto, Ont.) Nov 2022Kruppel-associated box (KRAB) proteins reportedly play a dual role in neoplastic transformation. At present, little is known about the function of the proteins encoded...
OBJECTIVE
Kruppel-associated box (KRAB) proteins reportedly play a dual role in neoplastic transformation. At present, little is known about the function of the proteins encoded by the human pogo transposable element derived with KRAB domain (POGK) gene. Herein, we evaluated the prognostic significance of POGK expression in patients with hepatocellular carcinoma (HCC).
METHODS
The data of HCC patients was downloaded from The Cancer Genome Atlas (TCGA) database. To determine the relationship between POGK and clinical features, logistic regression was applied. Cox regression and Kaplan-Meier analyses were used to evaluate the correlation between POGK and survival rates. Gene ontology (GO) analysis and Gene set enrichment analysis (GSEA) were conducted to identify the enriched pathways and functions associated with POGK.
RESULTS
A total of 374 HCC patients were identified in TCGA. POGK was significantly upregulated in HCC and correlated with tumor status ( = 0.036), race ( = 0.025), weight ( = 0.002), body mass index ( = 0.033), histologic grade ( < 0.001), and alpha-fetoprotein ( < 0.001). High POGK expression in HCC patients correlated with a poor outcome in terms of overall survival ( = 0.0018), progression-free survival ( = 0.0087), relapse-free survival ( = 0.045), and disease-specific survival ( = 0.014), according to Kaplan-Meier analysis. Receiver operating characteristic curve analysis showed that the area under the curve of POGK expression for HCC diagnosis was 0.891. GSEA showed that high POGK expression might activate mitotic prometaphase, kinesins, homologous DNA pairing and strand exchange, MET activates PTK2 signaling pathway, G1 to S cell cycle control, Aurora B pathway, ncRNAs involved in WNT signaling pathway, hepatitis C, and ncRNAs involved in the STAT3 signaling pathway. POGK expression correlated with the abundance of adaptive and innate immunocytes in HCC.
CONCLUSION
High expression of POGK has high diagnostic and prognostic values in patients with HCC. Moreover, POGK expression is correlated with immune infiltration in HCC.
Topics: Humans; Carcinoma, Hepatocellular; Liver Neoplasms; Gene Expression Regulation, Neoplastic; Biomarkers, Tumor; Neoplasm Recurrence, Local; Prognosis
PubMed: 36421335
DOI: 10.3390/curroncol29110682 -
BioRxiv : the Preprint Server For... Aug 2023The mammalian RAD52 protein is a DNA repair factor that has both strand annealing and recombination mediator activities, yet is dispensable for cell viability. To...
The mammalian RAD52 protein is a DNA repair factor that has both strand annealing and recombination mediator activities, yet is dispensable for cell viability. To characterize genetic contexts that reveal dependence on RAD52 to sustain cell viability (i.e., synthetic lethal relationships), we performed genome-wide CRISPR knock-out screens. Subsequent secondary screening found that depletion of ERCC6L in RAD52-deficient cells causes reduced viability and elevated genome instability, measured as accumulation of 53BP1 into nuclear foci. Furthermore, loss of RAD52 causes elevated levels of anaphase ultrafine bridges marked by ERCC6L, and conversely depletion of ERCC6L causes elevated RAD52 foci both in prometaphase and interphase cells. These effects were enhanced with combination treatments using hydroxyurea and the topoisomerase IIα inhibitor ICRF-193, and the timing of these treatments are consistent with defects in addressing such stress in mitosis. Thus, loss of RAD52 appears to cause an increased reliance on ERCC6L in mitosis, and vice versa. Consistent with this notion, combined depletion of ERCC6L and disrupting G2/M progression via CDK1 inhibition causes a marked loss of viability in RAD52-deficient cells. We suggest that RAD52 and ERCC6L play compensatory roles in protecting genome stability in mitosis.
PubMed: 37662271
DOI: 10.1101/2023.08.23.554522 -
Molecular Biology of the Cell Nov 2021The protein Slk19 has been shown to localize to kinetochores throughout mitosis and to the spindle midzone in anaphase. However, Slk19 clearly also has an important...
The protein Slk19 has been shown to localize to kinetochores throughout mitosis and to the spindle midzone in anaphase. However, Slk19 clearly also has an important role for spindle formation and stabilization in prometaphase and metaphase, albeit this role is unresolved. Here we show that Slk19's localization to metaphase spindles in vivo and to microtubules (MTs) in vitro depends on the MT cross-linking protein Ase1 and the MT cross-linking and stabilizing protein Stu1. By analyzing a mutant that specifically fails to localize to spindles and MTs, we surprisingly found that the presence of Slk19 amplified the amount of Ase1 strongly and that of Stu1 moderately at the metaphase spindle in vivo and at MTs in vitro. Furthermore, Slk19 markedly enhanced the cross-linking of MTs in vitro when added together with Ase1 or Stu1. We therefore suggest that Slk19 recruits additional Ase1 and Stu1 to the interpolar MTs (ipMTs) of metaphase spindles and thus increases their cross-linking and stabilization. This is in agreement with our observation that cells with defective Slk19 localization exhibit shorter metaphase spindles, an increased number of unaligned nuclear MTs, and most likely reduced ipMT overlaps.
Topics: Cell Cycle; Cell Nucleus; Kinetochores; Metaphase; Microtubule-Associated Proteins; Microtubules; Mitosis; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Spindle Apparatus
PubMed: 34495712
DOI: 10.1091/mbc.E21-05-0279 -
PLoS Genetics Jan 2023The conserved two-component XMAP215/TACC modulator of microtubule stability is required in multiple animal phyla for acentrosomal spindle assembly during oocyte meiotic...
The conserved two-component XMAP215/TACC modulator of microtubule stability is required in multiple animal phyla for acentrosomal spindle assembly during oocyte meiotic cell division. In C. elegans, XMAP215/zyg-9 and TACC/tac-1 mutant oocytes exhibit multiple and indistinguishable oocyte spindle assembly defects beginning early in meiosis I. To determine if these defects represent one or more early requirements with additional later and indirect consequences, or multiple temporally distinct and more direct requirements, we have used live cell imaging and fast-acting temperature-sensitive zyg-9 and tac-1 alleles to dissect their requirements at high temporal resolution. Temperature upshift and downshift experiments indicate that the ZYG-9/TAC-1 complex has multiple temporally distinct and separable requirements throughout oocyte meiotic cell division. First, we show that during prometaphase ZYG-9 and TAC-1 promote the coalescence of early pole foci into a bipolar structure, stabilizing pole foci as they grow and limiting their growth rate, with these requirements being independent of an earlier defect in microtubule organization that occurs upon nuclear envelope breakdown. Second, during metaphase, ZYG-9 and TAC-1 maintain spindle bipolarity by suppressing ectopic pole formation. Third, we show that ZYG-9 and TAC-1 also are required for spindle assembly during meiosis II, independently of their meiosis I requirements. The metaphase pole stability requirement appears to be important for maintaining chromosome congression, and we discuss how negative regulation of microtubule stability by ZYG-9/TAC-1 during oocyte meiotic cell division might account for the observed defects in spindle pole coalescence and stability.
Topics: Animals; Caenorhabditis elegans; Spindle Apparatus; Microtubules; Spindle Poles; Meiosis; Oocytes
PubMed: 36608115
DOI: 10.1371/journal.pgen.1010363 -
Bioinformatics (Oxford, England) Jun 2022Lattice light-sheet microscopy (LLSM) is revolutionizing cell biology since it enables fast, high-resolution extended imaging in three dimensions combined with a drastic...
MOTIVATION
Lattice light-sheet microscopy (LLSM) is revolutionizing cell biology since it enables fast, high-resolution extended imaging in three dimensions combined with a drastic reduction in photo-toxicity and bleaching. However, analysis of such datasets still remains a major challenge.
RESULTS
Automated tracking of kinetochores, the protein complex facilitating and controlling microtubule attachment of the chromosomes within the mitotic spindle, provides quantitative assessment of chromosome dynamics in mitosis. Here, we extend existing open-source kinetochore tracking software (KiT) to track (and pair) kinetochores throughout prometaphase to anaphase in LLSM data. One of the key improvements is a regularization term in the objective function to enforce biological information about the number of kinetochores in a human mitotic cell, as well as improved diagnostic tools. This software provides quantitative insights into how kinetochores robustly ensure congression and segregation of chromosomes during mitosis.
AVAILABILITY AND IMPLEMENTATION
KiT is free, open-source software implemented in MATLAB and can be downloaded as a package from https://github.com/cmcb-warwick/KiT. The source repository is available at https://bitbucket.org/jarmond/kit (tag v2.4.0) and under continuing development.
SUPPLEMENTARY INFORMATION
Supplementary data are available at Bioinformatics online.
Topics: Humans; Kinetochores; Spindle Apparatus; Anaphase; Microtubules; Software; Chromosome Segregation
PubMed: 35579370
DOI: 10.1093/bioinformatics/btac330 -
Molecular Biology of the Cell May 2023The human centromere comprises large arrays of repetitive α-satellite DNA at the primary constriction of mitotic chromosomes. In addition, centromeres are...
The human centromere comprises large arrays of repetitive α-satellite DNA at the primary constriction of mitotic chromosomes. In addition, centromeres are epigenetically specified by the centromere-specific histone H3 variant CENP-A that supports kinetochore assembly to enable chromosome segregation. Because CENP-A is bound to only a fraction of the α-satellite elements within the megabase-sized centromere DNA, correlating the three-dimensional (3D) organization of α-satellite DNA and CENP-A remains elusive. To visualize centromere organization within a single chromatid, we used a combination of the centromere chromosome orientation fluorescence in situ hybridization (Cen-CO-FISH) technique together with structured illumination microscopy. Cen-CO-FISH allows the differential labeling of the sister chromatids without the denaturation step used in conventional FISH that may affect DNA structure. Our data indicate that α-satellite DNA is arranged in a ring-like organization within prometaphase chromosomes, in the presence or absence of spindle's microtubules. Using expansion microscopy, we found that CENP-A organization within mitotic chromosomes follows a rounded pattern similar to that of α-satellite DNA, often visible as a ring thicker at the outer surface oriented toward the kinetochore-microtubule interface. Collectively, our data provide a 3D reconstruction of α-satellite DNA along with CENP-A clusters that outlines the overall architecture of the mitotic centromere.
Topics: Humans; DNA, Satellite; Centromere Protein A; Microscopy; In Situ Hybridization, Fluorescence; Chromosomal Proteins, Non-Histone; Autoantigens; Centromere; DNA
PubMed: 36947236
DOI: 10.1091/mbc.E22-08-0332 -
Pharmaceutics Sep 2021Ewing's sarcoma, characterized by pathognomonic t (11; 22) (q24; q12) and related chromosomal ETS family translocations, is a rare aggressive cancer of bone and soft...
Ewing's sarcoma, characterized by pathognomonic t (11; 22) (q24; q12) and related chromosomal ETS family translocations, is a rare aggressive cancer of bone and soft tissue. Current protocols that include cytotoxic chemotherapeutic agents effectively treat localized disease; however, these aggressive therapies may result in treatment-related morbidities including second-site cancers in survivors. Moreover, the five-year survival rate in patients with relapsed, recurrent, or metastatic disease is less than 30%, despite intensive therapy with these cytotoxic agents. By using high-throughput phenotypic screening of small molecule libraries, we identified a previously uncharacterized compound (ML111) that inhibited in vitro proliferation of six established Ewing's sarcoma cell lines with nanomolar potency. Proteomic studies show that ML111 treatment induced prometaphase arrest followed by rapid caspase-dependent apoptotic cell death in Ewing's sarcoma cell lines. ML111, delivered via methoxypoly(ethylene glycol)-polycaprolactone copolymer nanoparticles, induced dose-dependent inhibition of Ewing's sarcoma tumor growth in a murine xenograft model and invoked prometaphase arrest in vivo, consistent with in vitro data. These results suggest that ML111 represents a promising new drug lead for further preclinical studies and is a potential clinical development for the treatment of Ewing's sarcoma.
PubMed: 34683845
DOI: 10.3390/pharmaceutics13101553