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1.
J Cell Sci ; 136(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36594556

RESUMO

Cancer cells have heterogeneous fitness, and this heterogeneity stems from genetic and epigenetic sources. Here, we sought to assess the contribution of asymmetric mitosis (AM) and time on the variability of fitness in sister cells. Around one quarter of sisters had differences in fitness, assessed as the intermitotic time (IMT), from 330 to 510 min. Phenotypes related to fitness, such as ERK activity (herein referring to ERK1 and ERK2, also known as MAPK3 and MAPK1, respectively), DNA damage and nuclear morphological phenotypes were also asymmetric at mitosis or turned asymmetric over the course of the cell cycle. The ERK activity of mother cell was found to influence the ERK activity and the IMT of the daughter cells, and cells with ERK asymmetry at mitosis produced more offspring with AMs, suggesting heritability of the AM phenotype for ERK activity. Our findings demonstrate how variabilities in sister cells can be generated, contributing to the phenotype heterogeneities in tumor cells.


Assuntos
Divisão do Núcleo Celular , Mitose , Mitose/genética , Ciclo Celular , Fosforilação , Células-Tronco
2.
Sci Rep ; 12(1): 20902, 2022 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-36463288

RESUMO

Breast cancer (BC) cell lines are useful experimental models to understand cancer biology. Yet, their relevance to modelling cancer remains unclear. To better understand the tumour-modelling efficacy of cell lines, we performed RNA-seq analyses on a combined dataset of 2D and 3D cultures of tumourigenic MCF7 and non-tumourigenic MCF10A. To our knowledge, this was the first RNA-seq dataset comprising of 2D and 3D cultures of MCF7 and MCF10A within the same experiment, which facilitates the elucidation of differences between MCF7 and MCF10A across culture types. We compared the genes and gene sets distinguishing MCF7 from MCF10A against separate RNA-seq analyses of clinical luminal A (LumA) and normal samples from the TCGA-BRCA dataset. Among the 1031 cancer-related genes distinguishing LumA from normal samples, only 5.1% and 15.7% of these genes also distinguished MCF7 from MCF10A in 2D and 3D cultures respectively, suggesting that different genes drive cancer-related differences in cell lines compared to clinical BC. Unlike LumA tumours which showed increased nuclear division-related gene expression compared to normal tissue, nuclear division-related gene expression in MCF7 was similar to MCF10A. Moreover, although LumA tumours had similar cell adhesion-related gene expression compared to normal tissues, MCF7 showed reduced cell adhesion-related gene expression compared to MCF10A. These findings suggest that MCF7 and MCF10A cell lines were limited in their ability to model cancer-related processes in clinical LumA tumours.


Assuntos
Divisão do Núcleo Celular , Transcriptoma , Humanos , Adesão Celular/genética , Células MCF-7 , RNA-Seq
3.
Med Oncol ; 40(1): 14, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36352167

RESUMO

Hepatocellular carcinoma is the cancer with the highest incidence among liver cancers and how to treat this cancer effectively is still a difficult problem we must face. We selected meiotic nuclear divisions 1 (MND1) as the study object by combining data from The Cancer Genome Atlas (TCGA) database with prognostic survival analysis. We validated the value of MND1 in evaluating the prognosis of hepatocellular carcinoma through a diagnostic and prognostic model. At the same time, cellular experiments were used to demonstrate the effect of MND1 on hepatocellular carcinoma proliferation and migration. We used short hairpin RNA (shRNA) to knock down MND1 in Hun7 and HCCLM3 cell lines. Through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assays, we found that knocking down MND1 reduced the proliferation of cells. Through wound healing and Transwell assays, we found that knocking down MND1 reduced cell migration and invasion. Moreover, we found that MND1 can promote the proliferation, migration, and invasion of Hep3B cells by overexpressing MND1. Therefore, in general, MND1 is expected to be a gene that can effectively diagnose and treat hepatocellular carcinoma.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Proliferação de Células/genética , Linhagem Celular Tumoral , RNA Interferente Pequeno , Divisão do Núcleo Celular , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica , Invasividade Neoplásica/genética
4.
Int J Mol Sci ; 23(19)2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36232691

RESUMO

CENP-A is a histone variant found in high abundance at the centromere in humans. At the centromere, this histone variant replaces the histone H3 found throughout the bulk chromatin. Additionally, the centromere comprises tandem repeats of α-satellite DNA, which CENP-A nucleosomes assemble upon. However, the effect of the DNA sequence on the nucleosome assembly and centromere formation remains poorly understood. Here, we investigated the structure of nucleosomes assembled with the CENP-A variant using Atomic Force Microscopy. We assembled both CENP-A nucleosomes and H3 nucleosomes on a DNA substrate containing an α-satellite motif and characterized their positioning and wrapping efficiency. We also studied CENP-A nucleosomes on the 601-positioning motif and non-specific DNA to compare their relative positioning and stability. CENP-A nucleosomes assembled on α-satellite DNA did not show any positional preference along the substrate, which is similar to both H3 nucleosomes and CENP-A nucleosomes on non-specific DNA. The range of nucleosome wrapping efficiency was narrower on α-satellite DNA compared with non-specific DNA, suggesting a more stable complex. These findings indicate that DNA sequence and histone composition may be two of many factors required for accurate centromere assembly.


Assuntos
Divisão do Núcleo Celular , Proteína Centromérica A , Centrômero , DNA , Histonas , Nucleossomos , Autoantígenos/química , Autoantígenos/genética , Divisão do Núcleo Celular/genética , Divisão do Núcleo Celular/fisiologia , Centrômero/genética , Centrômero/metabolismo , Proteína Centromérica A/genética , Proteína Centromérica A/metabolismo , Cromatina/genética , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , DNA/química , DNA/genética , DNA/metabolismo , DNA Satélite , Histonas/genética , Histonas/metabolismo , Humanos , Microscopia de Força Atômica , Nucleossomos/genética , Nucleossomos/metabolismo
5.
J Clin Lab Anal ; 36(9): e24647, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35949045

RESUMO

BACKGROUND: Kinesin family member 2A (KIF2A), nuclear division cycle 80 (NDC80), cyclin-dependent kinase 1 (CDK1), and cyclin B1 (CCNB1) exhibit a complex interrelation, which promote cancer progression via multiple ways, whereas their interaction and clinical implications in breast cancer are obscure. Hence, this study aimed to evaluate the correlation among KIF2A, NDC80, CDK1, CCNB1, and their linkage with clinicopathological features and prognosis in breast cancer patients. METHODS: 195 breast cancer patients underwent surgical resection were analyzed. KIF2A, NDC80, CDK1, and CCNB1 expressions were determined by immunohistochemical (IHC) assay and scored by a semiquantitative IHC score or positive cell percentage. RESULTS: KIF2A expression positively associated with NDC80, CDK1, and CCNB1 expressions (all p < 0.01). In terms of tumor features: KIF2A high expression linked with increased T stage (p = 0.011), N stage (p = 0.014), and TNM stage (p = 0.009) but not tumor differentiation (p = 0.651). NDC80 high expression only related to higher N stage (p = 0.010); CDK1 high expression only connected with elevated N stage (p = 0.035) and TNM stage (p = 0.023). In aspect of prognosis, high expression of KIF2A was correlated with worse disease-free survival (DFS) (p = 0.031), while NDC80 high (p = 0.329), CDK1 high (p = 0.276), and CCNB1 positive (p = 0.063) expressions only showed trends to link with poor DFS (without statistical significance). Furthermore, high expression of KIF2A (p = 0.063), NDC80 (p = 0.939), CDK1 (p = 0.413) and positive expression of CCNB1 (p = 0.296) did not relate to overall survival. CONCLUSION: KIF2A correlates with NDC80, CDK1, CCNB1, and may link with advanced tumor stages and poor prognosis in breast cancer patients.


Assuntos
Neoplasias da Mama , Proteína Quinase CDC2 , Neoplasias da Mama/patologia , Divisão do Núcleo Celular , Ciclina B1/genética , Proteínas do Citoesqueleto , Feminino , Humanos , Cinesinas , Prognóstico
6.
Nucleus ; 13(1): 144-154, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35298348

RESUMO

Dictyostelium amoebae perform a semi-closed mitosis, in which the nuclear envelope is fenestrated at the insertion sites of the mitotic centrosomes and around the central spindle during karyokinesis. During late telophase the centrosome relocates to the cytoplasmic side of the nucleus, the central spindle disassembles and the nuclear fenestrae become closed. Our data indicate that Dictyostelium spastin (DdSpastin) is a microtubule-binding and severing type I membrane protein that plays a role in this process. Its mitotic localization is in agreement with a requirement for the removal of microtubules that would hinder closure of the fenestrae. Furthermore, DdSpastin interacts with the HeH/ LEM-family protein Src1 in BioID analyses as well as the inner nuclear membrane protein Sun1, and shows subcellular co-localizations with Src1, Sun1, the ESCRT component CHMP7 and the IST1-like protein filactin, suggesting that the principal pathway of mitotic nuclear envelope remodeling is conserved between animals and Dictyostelium amoebae.


Assuntos
Dictyostelium , Membrana Nuclear , Animais , Divisão do Núcleo Celular , Dictyostelium/metabolismo , Mitose , Membrana Nuclear/metabolismo , Espastina/metabolismo
7.
Nat Commun ; 13(1): 772, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35140224

RESUMO

Embryogenesis depends on a tightly regulated balance between mitosis, differentiation, and morphogenesis. Understanding how the embryo uses a relatively small number of proteins to transition between growth and morphogenesis is a central question of developmental biology, but the mechanisms controlling mitosis and differentiation are considered to be fundamentally distinct. Here we show the mitotic kinase Polo, which regulates all steps of mitosis in Drosophila, also directs cellular morphogenesis after cell cycle exit. In mitotic cells, the Aurora kinases activate Polo to control a cytoskeletal regulatory module that directs cytokinesis. We show that in the post-mitotic mesoderm, the control of Polo activity transitions from the Aurora kinases to the uncharacterized kinase Back Seat Driver (Bsd), where Bsd and Polo cooperate to regulate muscle morphogenesis. Polo and its effectors therefore direct mitosis and cellular morphogenesis, but the transition from growth to morphogenesis is determined by the spatiotemporal expression of upstream activating kinases.


Assuntos
Drosophila/metabolismo , Mitose , Morfogênese/fisiologia , Fosfotransferases/metabolismo , Animais , Aurora Quinases/metabolismo , Ciclo Celular , Proteínas de Ciclo Celular/metabolismo , Divisão do Núcleo Celular , Citocinese , Drosophila/genética , Proteínas de Drosophila , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Associadas aos Microtúbulos , Morfogênese/genética , Fosfotransferases/genética , Fuso Acromático/metabolismo
8.
Development ; 149(2)2022 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-35001104

RESUMO

Biological systems are highly complex, yet notably ordered structures can emerge. During syncytial stage development of the Drosophila melanogaster embryo, nuclei synchronously divide for nine cycles within a single cell, after which most of the nuclei reach the cell cortex. The arrival of nuclei at the cortex occurs with remarkable positional order, which is important for subsequent cellularisation and morphological transformations. Yet, the mechanical principles underlying this lattice-like positional order of nuclei remain untested. Here, using quantification of nuclei position and division orientation together with embryo explants, we show that short-ranged repulsive interactions between microtubule asters ensure the regular distribution and maintenance of nuclear positions in the embryo. Such ordered nuclear positioning still occurs with the loss of actin caps and even the loss of the nuclei themselves; the asters can self-organise with similar distribution to nuclei in the wild-type embryo. The explant assay enabled us to deduce the nature of the mechanical interaction between pairs of nuclei. We used this to predict how the nuclear division axis orientation changes upon nucleus removal from the embryo cortex, which we confirmed in vivo with laser ablation. Overall, we show that short-ranged microtubule-mediated repulsive interactions between asters are important for ordering in the early Drosophila embryo and minimising positional irregularity.


Assuntos
Blastoderma/metabolismo , Divisão do Núcleo Celular , Células Gigantes/metabolismo , Animais , Blastoderma/citologia , Núcleo Celular/metabolismo , Drosophila melanogaster , Células Gigantes/citologia , Microtúbulos/metabolismo , Estresse Mecânico
9.
Nan Fang Yi Ke Da Xue Xue Bao ; 41(10): 1509-1518, 2021 Oct 20.
Artigo em Chinês | MEDLINE | ID: mdl-34755666

RESUMO

OBJECTIVE: To identify the key genes involved in the transformation of hepatitis B virus (HBV) into hepatocellular carcinoma (HCC) and explore the underlying molecular mechanisms. METHODS: We analyzed the mRNA microarray data of 119 HBV-related HCC tissues and 252 HBV-related non-tumor tissues in GSE55092, GSE84044 and GSE121248 from the GEO database, and the "sva" R package was used to remove the batch effects. Integration analysis was performed to identify the differentially expressed genes (DEGs) in HBV-related liver cancer and liver tissues with HBV infection. The significant DEGs were functionally annotated using GO and KEGG analyses, and the most important modules and hub genes were explored with STRING analysis. Kaplan-Meier and Oncomine databases were used to verify the HCC gene expression data in the TCGA database to explore the correlations of the hub genes with the occurrence, progression and prognosis of HCC. We also examined the expressions of the hub genes in 17 pairs of surgical specimens of HCC and adjacent tissues using RT-qPCR. RESULTS: We identified a total of 121 DEGs and 3 genetic markers in HCC (P < 0.01). These DEGs included cyclin1 (CDK1), cyclin B1 (CCNB1), and nuclear division cycle 80 (NDC80), which participated in cell cycle, pyrimidine metabolism and DNA replication and were highly correlated (P < 0.05). Analysis of the UALCAN database confirmed high expressions of these 3 genes in HCC tissues, which were correlated with a low survival rate of the patients, as shown by Kaplan-Meier analysis of the prognostic data from the UALCAN database. CDK1, CCNB1 and NDC80 were all correlated with the clinical grading of HCC (P < 0.05). The results of RT-qPCR on the surgical specimens verified significantly higher expressions of CDK1, CCNB1 and NDC80 mRNA in HCC tissues than in the adjacent tissues. CONCLUSION: CDK1, CCNB1 and NDC80 genes can be used as prognostic markers of HBV-related HCC and may serve as potential targets in preclinical studies and clinical treatment of HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Proteína Quinase CDC2/genética , Carcinoma Hepatocelular/genética , Divisão do Núcleo Celular , Biologia Computacional , Ciclina B1/genética , Proteínas do Citoesqueleto , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Vírus da Hepatite B/genética , Humanos , Neoplasias Hepáticas/genética , Prognóstico
10.
Curr Biol ; 31(18): 4104-4110.e5, 2021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34293333

RESUMO

The evolutionary path from protists to multicellular animals remains a mystery. Recent work on the genomes of several unicellular relatives of animals has shaped our understanding of the genetic changes that may have occurred in this transition.1-3 However, the specific cellular modifications that took place to accommodate these changes remain unclear. To address this, we need to compare metazoan cells with those of their extant relatives, which are choanoflagellates, filastereans, ichthyosporeans, and corallochytreans/pluriformeans. Interestingly, these lineages display a range of developmental patterns potentially homologous to animal ones. Genetic tools have already been established in three of those lineages.4-7 However, there are no genetic tools available for Corallochytrea. We here report the development of stable transfection in the corallochytrean Corallochytrium limacisporum. Using these tools, we discern previously unknown biological features of C. limacisporum. In particular, we identify two different paths for cell division-binary fission and coenocytic growth-that reveal a non-linear life cycle. Additionally, we found that C. limacisporum is binucleate for most of its life cycle, and that, contrary to what happens in most eukaryotes, nuclear division is decoupled from cellular division. Moreover, its actin cytoskeleton shares characteristics with both fungal and animal cells. The establishment of these tools in C. limacisporum fills an important gap in the unicellular relatives of animals, opening up new avenues of research to elucidate the specific cellular changes that occurred in the evolution of animals.


Assuntos
Eucariotos , Fungos , Animais , Divisão do Núcleo Celular , Eucariotos/genética , Fungos/genética , Filogenia , Transfecção
11.
Dev Cell ; 56(15): 2192-2206.e8, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34331869

RESUMO

To generate haploid gametes, germ cells undergo two consecutive meiotic divisions requiring key changes to the cell division machinery. Here, we demonstrate that the protease separase rewires key cell division processes at the meiosis I/II transition by cleaving the meiosis-specific protein Meikin. Separase proteolysis does not inactivate Meikin but instead alters its function to create a distinct activity state. Full-length Meikin and the C-terminal Meikin separase cleavage product both localize to kinetochores, bind to Plk1 kinase, and promote Rec8 cleavage, but our results reveal distinct roles for these proteins in controlling meiosis. Mutations that prevent Meikin cleavage or that conditionally inactivate Meikin at anaphase I result in defective meiosis II chromosome alignment in mouse oocytes. Finally, as oocytes exit meiosis, C-Meikin is eliminated by APC/C-mediated degradation prior to the first mitotic division. Thus, multiple regulatory events irreversibly modulate Meikin activity during successive meiotic divisions to rewire the cell division machinery at two distinct transitions.


Assuntos
Proteínas Cromossômicas não Histona/metabolismo , Meiose/fisiologia , Separase/metabolismo , Animais , Animais não Endogâmicos , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/fisiologia , Divisão Celular/fisiologia , Divisão do Núcleo Celular , Centrômero/metabolismo , Proteínas Cromossômicas não Histona/fisiologia , Segregação de Cromossomos , Feminino , Células HeLa , Humanos , Cinetocoros/metabolismo , Camundongos , Oócitos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/fisiologia , Separase/fisiologia
12.
Epigenetics Chromatin ; 14(1): 34, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34301312

RESUMO

Histone chaperones facilitate DNA replication and repair by promoting chromatin assembly, disassembly and histone exchange. Following histones synthesis and nucleosome assembly, the histones undergo posttranslational modification by different enzymes and are deposited onto chromatins by various histone chaperones. In Tetrahymena thermophila, histones from macronucleus (MAC) and micronucleus (MIC) have been comprehensively investigated, but the function of histone chaperones remains unclear. Histone chaperone Nrp1 in Tetrahymena contains four conserved tetratricopepeptide repeat (TPR) domains and one C-terminal nuclear localization signal. TPR2 is typically interrupted by a large acidic motif. Immunofluorescence staining showed that Nrp1 is located in the MAC and MICs, but disappeared in the apoptotic parental MAC and the degraded MICs during the conjugation stage. Nrp1 was also colocalized with α-tubulin around the spindle structure. NRP1 knockdown inhibited cellular proliferation and led to the loss of chromosome, abnormal macronuclear amitosis, and disorganized micronuclear mitosis during the vegetative growth stage. During sexual developmental stage, the gametic nuclei failed to be selected and abnormally degraded in NRP1 knockdown mutants. Affinity purification combined with mass spectrometry analysis indicated that Nrp1 is co-purified with core histones, heat shock proteins, histone chaperones, and DNA damage repair proteins. The physical direct interaction of Nrp1 and Asf1 was also confirmed by pull-down analysis in vitro. The results show that histone chaperone Nrp1 is involved in micronuclear mitosis and macronuclear amitosis in the vegetative growth stage and maintains gametic nuclei formation during the sexual developmental stage. Nrp1 is required for chromatin stability and nuclear division in Tetrahymena thermophila.


Assuntos
Tetrahymena thermophila , Divisão do Núcleo Celular , Cromatina , Cromossomos , Chaperonas de Histonas/genética , Tetrahymena thermophila/genética
13.
Mol Biol Cell ; 32(20): br3, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34319762

RESUMO

Force generation by the molecular motor myosin II (MII) at the actin cortex is a universal feature of animal cells. Despite its central role in driving cell shape changes, the mechanisms underlying MII regulation at the actin cortex remain incompletely understood. Here we show that myosin light chain kinase (MLCK) promotes MII turnover at the mitotic cortex. Inhibition of MLCK resulted in an alteration of the relative levels of phosphorylated regulatory light chain (RLC), with MLCK preferentially creating a short-lived pRLC species and Rho-associated kinase (ROCK) preferentially creating a stable ppRLC species during metaphase. Slower turnover of MII and altered RLC homeostasis on MLCK inhibition correlated with increased cortex tension, driving increased membrane bleb initiation and growth, but reduced bleb retraction during mitosis. Taken together, we show that ROCK and MLCK play distinct roles at the actin cortex during mitosis; ROCK activity is required for recruitment of MII to the cortex, while MLCK activity promotes MII turnover. Our findings support the growing evidence that MII turnover is an essential dynamic process influencing the mechanical output of the actin cortex.


Assuntos
Actinas/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Miosina Tipo II/metabolismo , Quinase de Cadeia Leve de Miosina/metabolismo , Vesícula/metabolismo , Proteínas de Ligação ao Cálcio/fisiologia , Divisão do Núcleo Celular , Proteínas do Citoesqueleto/metabolismo , Células HeLa , Humanos , Mitose/fisiologia , Cadeias Leves de Miosina/metabolismo , Miosina Tipo II/fisiologia , Quinase de Cadeia Leve de Miosina/fisiologia , Fosforilação , Quinases Associadas a rho/metabolismo
14.
Curr Biol ; 31(18): 3973-3983.e4, 2021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34297912

RESUMO

Although nuclei are the defining features of eukaryotes, we still do not fully understand how the nuclear compartment is duplicated and partitioned during division. This is especially the case for organisms that do not completely disassemble their nuclear envelope upon entry into mitosis. In studying this process in Drosophila neural stem cells, which undergo asymmetric divisions, we find that the nuclear compartment boundary persists during mitosis thanks to the maintenance of a supporting nuclear lamina. This mitotic nuclear envelope is then asymmetrically remodeled and partitioned to give rise to two daughter nuclei that differ in envelope composition and exhibit a >30-fold difference in volume. The striking difference in nuclear size was found to depend on two consecutive processes: asymmetric nuclear envelope resealing at mitotic exit at sites defined by the central spindle, and differential nuclear growth that appears to depend on the available local reservoir of ER/nuclear membranes, which is asymmetrically partitioned between the two daughter cells. Importantly, these asymmetries in size and composition of the daughter nuclei, and the associated asymmetries in chromatin organization, all become apparent long before the cortical release and the nuclear import of cell fates determinants. Thus, asymmetric nuclear remodeling during stem cell divisions may contribute to the generation of cellular diversity by initiating distinct transcriptional programs in sibling nuclei that contribute to later changes in daughter cell identity and fate.


Assuntos
Células-Tronco Neurais , Irmãos , Núcleo Celular , Divisão do Núcleo Celular , Cromatina , Humanos , Mitose , Membrana Nuclear
15.
PLoS Genet ; 17(4): e1009327, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33901174

RESUMO

The Aurora protein kinases are well-established regulators of spindle building and chromosome segregation in mitotic and meiotic cells. In mouse oocytes, there is significant Aurora kinase A (AURKA) compensatory abilities when the other Aurora kinase homologs are deleted. Whether the other homologs, AURKB or AURKC can compensate for loss of AURKA is not known. Using a conditional mouse oocyte knockout model, we demonstrate that this compensation is not reciprocal because female oocyte-specific knockout mice are sterile, and their oocytes fail to complete meiosis I. In determining AURKA-specific functions, we demonstrate that its first meiotic requirement is to activate Polo-like kinase 1 at acentriolar microtubule organizing centers (aMTOCs; meiotic spindle poles). This activation induces fragmentation of the aMTOCs, a step essential for building a bipolar spindle. We also show that AURKA is required for regulating localization of TACC3, another protein required for spindle building. We conclude that AURKA has multiple functions essential to completing MI that are distinct from AURKB and AURKC.


Assuntos
Aurora Quinase A/genética , Proteínas de Ciclo Celular/genética , Proteínas Fetais/genética , Meiose/genética , Proteínas Associadas aos Microtúbulos/genética , Oócitos/crescimento & desenvolvimento , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Animais , Aurora Quinase B/genética , Aurora Quinase C/genética , Divisão do Núcleo Celular/genética , Segregação de Cromossomos/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Humanos , Camundongos , Centro Organizador dos Microtúbulos/metabolismo , Oócitos/metabolismo , Fuso Acromático/genética , Polos do Fuso/genética
16.
Cancer Commun (Lond) ; 41(6): 492-510, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33734616

RESUMO

BACKGROUND: Considering the increase in the proportion of lung adenocarcinoma (LUAD) cases among all lung cancers and its considerable contribution to cancer-related deaths worldwide, we sought to identify novel oncogenes to provide potential targets and facilitate a better understanding of the malignant progression of LUAD. METHODS: The results from the screening of transcriptome and survival analyses according to the integrated Gene Expression Omnibus (GEO) datasets and The Cancer Genome Atlas (TCGA) data were combined, and a promising risk biomarker called meiotic nuclear divisions 1 (MND1) was selectively acquired. Cell viability assays and subcutaneous xenograft models were used to validate the oncogenic role of MND1 in LUAD cell proliferation and tumor growth. A series of assays, including mass spectrometry, co-immunoprecipitation (Co-IP), and chromatin immunoprecipitation (ChIP), were performed to explore the underlying mechanism. RESULTS: MND1 up-regulation was identified to be an independent risk factor for overall survival in LUAD patients evaluated by both tissue microarray staining and third party data analysis. In vivo and in vitro assays showed that MND1 promoted LUAD cell proliferation by regulating cell cycle. The results of the Co-IP, ChIP and dual-luciferase reporter assays validated that MND1 competitively bound to tumor suppressor Kruppel-like factor 6 (KLF6), and thereby protecting E2F transcription factor 1 (E2F1) from KLF6-induced transcriptional repression. Luciferase reporter and ChIP assays found that E2F1 activated MND1 transcription by binding to its promoter in a feedback manner. CONCLUSIONS: MND1, KLF6, and E2F1 form a positive feedback loop to regulate cell cycle and confer DDP resistance in LUAD. MND1 is crucial for malignant progression and may be a potential therapeutic target in LUAD patients.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Adenocarcinoma de Pulmão/genética , Ciclo Celular/genética , Proteínas de Ciclo Celular , Divisão do Núcleo Celular , Fator de Transcrição E2F1/genética , Retroalimentação , Humanos , Fator 6 Semelhante a Kruppel , Neoplasias Pulmonares/genética
17.
Protoplasma ; 258(3): 621-632, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33389128

RESUMO

Magnolia, a basal angiosperm genus important for evolutionary and phylogenetic studies, is known to have male meiotic features not seen in the vast majority of angiosperms. However, knowledge about male meiosis in Magnolia is still fragmentary. Here, we report findings from an extensive investigation into male meiosis in Magnolia denudata using a combination of light and electron microscopy methods. Male meiosis in M. denudata was synchronous in prophase I but asynchronous in subsequent nuclear divisions. The polarized microspore mother cells from late prophase I onward had an elongated cell shape and thickened callose wall areas at the two smaller ends of the cell. The first nuclear division occurred along the long axis of the cell and the first callose furrow formed at the equatorial plane of the first nuclear division at the late telophase I stage. The second equatorial callose furrow formed after telophase II in a plane perpendicular to the first callose furrow. While cytokinesis occurred centripetally from the two furrows, a central callose wall island (CWI) appeared in the center of the cell and dense assemblies of vesicles and short tubules decorated the cytoplasmic regions between the furrows and the CWI. This cytokinesis mode differs from either the centripetal or the centrifugal mode of cytokinesis in microsporogenesis in the vast majority of angiosperms. As a result of this unusual cytokinesis, a large central callose mass remains in the mature tetrads. These observations may be useful to studies of cytokinetic mechanisms, evolution of microsporogenesis, and phylogenetics of angiosperms.


Assuntos
Divisão do Núcleo Celular/fisiologia , Polaridade Celular/fisiologia , Citocinese/fisiologia , Magnolia/química , Meiose/fisiologia
18.
Cell Cycle ; 20(2): 211-224, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33404279

RESUMO

Combining targeted therapeutic agents is an attractive cancer treatment strategy associated with high efficacy and low toxicity. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is an essential factor in DNA damage repair. Studies from us and others have revealed that DNA-PKcs also plays an important role in normal mitosis progression. Histone deacetylase (HDACs) inhibitors commonly lead to mitotic aberration and have been approved for treating various cancers in the clinic. We showed that DNA-PKcs depletion or kinase activity inhibition increases cancer cells' sensitivity to HDACs inhibitors in vitro and in vivo. DNA-PKcs deficiency significantly enhances HDACs inhibitors (HDACi)-induced mitotic arrest and is followed by apoptotic cell death. Mechanistically, we found that DNA-PKcs binds to HDAC6 and facilitates its acetylase activity. HDACi is more likely to impair HDAC6-induced deacetylation of HSP90 and abrogate HSP90's chaperone function on Aurora A, a critical mitotic kinase that regulates centrosome separation and mitotic spindle assembly in DNA-PKcs-deficient cells. Our current work indicates crosstalk between DNA-PKcs and HDACs signaling pathways, and highlights that the combined targeting of DNA-PKcs and HDACs can be used in cancer therapy. Abbreviations: DNA-PKcs, DNA-dependent protein kinase catalytic subunit, HDACs, Histone deacetylases, DSBs, DNA double-strand breaks, ATM, ataxia telangiectasia mutated, ATR, ATM-Rad3-related.


Assuntos
Proteína Quinase Ativada por DNA/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Desacetilase 6 de Histona/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Ciclo Celular/metabolismo , Divisão do Núcleo Celular/genética , Divisão do Núcleo Celular/fisiologia , Dano ao DNA/genética , Reparo do DNA/genética , Desacetilase 6 de Histona/genética , Humanos , Proteínas Supressoras de Tumor/metabolismo
19.
Cell Microbiol ; 23(3): e13284, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33124706

RESUMO

The eukaryotic cell cycle is typically divided into distinct phases with cytokinesis immediately following mitosis. To ensure proper cell division, each phase is tightly coordinated via feedback controls named checkpoints. During its asexual replication cycle, the malaria parasite Plasmodium falciparum undergoes multiple asynchronous rounds of mitosis with segregation of uncondensed chromosomes followed by nuclear division with intact nuclear envelope. The multi-nucleated schizont is then subjected to a single round of cytokinesis that produces dozens of daughter cells called merozoites. To date, no cell cycle checkpoints have been identified that regulate the Plasmodium spp. mode of division. Here, we identify the Plasmodium homologue of the Mini-Chromosome Maintenance Complex Binding Protein (PfMCMBP), which co-purified with the Mini-Chromosome Maintenance (MCM) complex, a replicative helicase required for genomic DNA replication. By conditionally depleting PfMCMBP, we disrupt nuclear morphology and parasite proliferation without causing a block in DNA replication. By immunofluorescence microscopy, we show that PfMCMBP depletion promotes the formation of mitotic spindle microtubules with extensions to more than one DNA focus and abnormal centrin distribution. Strikingly, PfMCMBP-deficient parasites complete cytokinesis and form aneuploid merozoites with variable cellular and nuclear sizes. Our study demonstrates that the parasite lacks a robust checkpoint response to prevent cytokinesis following aberrant karyokinesis.


Assuntos
Divisão do Núcleo Celular , Citocinese , Proteínas de Manutenção de Minicromossomo/metabolismo , Plasmodium falciparum/citologia , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Cromossomos/metabolismo , Cromossomos/ultraestrutura , Técnicas de Silenciamento de Genes , Merozoítos/citologia , Merozoítos/crescimento & desenvolvimento , Centro Organizador dos Microtúbulos/metabolismo , Centro Organizador dos Microtúbulos/ultraestrutura , Proteínas Nucleares/genética , Plasmodium falciparum/genética , Plasmodium falciparum/crescimento & desenvolvimento , Proteínas de Protozoários/genética , Esquizontes/fisiologia
20.
Medicine (Baltimore) ; 99(49): e22655, 2020 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-33285674

RESUMO

To explore the gene modules and key genes of head and neck squamous cell carcinoma (HNSCC), a bioinformatics algorithm based on the gene co-expression network analysis was proposed in this study.Firstly, differentially expressed genes (DEGs) were identified and a gene co-expression network (i-GCN) was constructed with Pearson correlation analysis. Then, the gene modules were identified with 5 different community detection algorithms, and the correlation analysis between gene modules and clinical indicators was performed. Gene Ontology (GO) analysis was used to annotate the biological pathways of the gene modules. Then, the key genes were identified with 2 methods, gene significance (GS) and PageRank algorithm. Moreover, we used the Disgenet database to search the related diseases of the key genes. Lastly, the online software onclnc was used to perform the survival analysis on the key genes and draw survival curves.There were 2600 up-regulated and 1547 down-regulated genes identified in HNSCC. An i-GCN was constructed with Pearson correlation analysis. Then, the i-GCN was divided into 9 gene modules. The result of association analysis showed that, sex was mainly related to mitosis and meiosis processes, event was mainly related to responding to interferons, viruses and T cell differentiation processes, T stage was mainly related to muscle development and contraction, regulation of protein transport activity processes, N stage was mainly related to mitosis and meiosis processes, while M stage was mainly related to responding to interferons and immune response processes. Lastly, 34 key genes were identified, such as CDKN2A, HOXA1, CDC7, PPL, EVPL, PXN, PDGFRB, CALD1, and NUSAP1. Among them, HOXA1, PXN, and NUSAP1 were negatively correlated with the survival prognosis.HOXA1, PXN, and NUSAP1 might play important roles in the progression of HNSCC and severed as potential biomarkers for future diagnosis.


Assuntos
Redes Reguladoras de Genes/fisiologia , Neoplasias de Cabeça e Pescoço/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Divisão do Núcleo Celular/fisiologia , Biologia Computacional/métodos , Regulação para Baixo , Ontologia Genética , Neoplasias de Cabeça e Pescoço/imunologia , Humanos , Fatores Sexuais , Carcinoma de Células Escamosas de Cabeça e Pescoço/imunologia , Linfócitos T/metabolismo , Regulação para Cima
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