995 research outputs found

    STRATEGI PDI-PERJUANGAN DALAM PEMENANGAN ANGGOTA LEGISLATIF DAERAH PEMILIHAN III DI TOMOHON SELATAN TAHUN 2019

    Get PDF
    Artikel ini akan mengkaji strategi yang dilakukan oleh Partai Demokrasi Indonesia Perjuangan dalam memenangkan para calon anggota legislatif khususnya di Daerah Pemilihan (Dapil) 3 di Tomohon Selatan Kota Tomohon Propinsi Sulawesi Utara pada pemilihan anggota legislatif tahun 2019. Penelitian ini dilakukan dengan menggunakan metode kualitatif. Temuan penelitian menggambarkan bahwa ada banyak strategi yang digunakan oleh PDI-Perjuangan dan calon dalam memenangkan pemilu 2019. Strategi yang digunakan mulai melakukan kegiatan sosial kemasyarakatan, pemasangan baliho, spanduk, dan kampanye, sosialisasi dan pendidikan politik kepada simpatisan dan masyarakat umum secara terus menerus dengan tujuan membentuk citra politik yang positif baik bagi partai maupun bagi calon-calon legislatif itu sendiri. Sedangkan strategi politik yang dilakukan oleh masing-masing calon legislatif mulai dari tahapan konsolidasi degan kader partai, ranting partai, serta anak ranting dan para pemilih dikalangan masyarakat umum secara intens dinilai sangat efektif dalam meningkatan perolehan suara caleg. Komunikasi langsung yang dilakukanan oleh masing-masing caleg dengan masyarakat memberi pengaruh sangat singnifikan.Walaupun hanya memperoleh 4 kursi legislatif namun strategi PDI-perjuangan sudah sangat baik terbukti dari suara pemilihan yang lebih banyak dibandingkan di periode sebelumnya. Disisi lain kualitas rectrutmen calon legislatif yang semakin ketat merupakan fondasi yang kokoh untuk PDI-Perjuangan melahirkan caleg yang mempunyai elektabilitas dan kualitas dalam memperjuangkan hak-hak msayarakat serta aspirasi masyarakat. Kata Kunci : Strategi Politik; PDIP; Pemilihan Anggota Legislatif  ABSTRACTThis article will examine the strategy adopted by the Indonesian Democratic Party of Struggle in winning legislative candidates, especially in the Electoral District (Dapil) 3 in South Tomohon, Tomohon City, North Sulawesi Province in the 2019 legislative elections. This research was conducted using a qualitative method. The research findings illustrate that there are many strategies used by PDI-Perjuangan and candidates in winning the 2019 election. The strategies used include carrying out social activities, installing billboards, banners, and campaigns, socialization and political education to sympathizers and the general public continuously with the goal is to form a positive political image for both the party and the legislative candidates themselves. Meanwhile, the political strategy carried out by each legislative candidate starting from the consolidation stage with party cadres, party branches, as well as branches and voters among the general public was intensely considered very effective in increasing the vote acquisition of candidates. The direct communication carried out by each legislative candidate with the community has a very significant impact. Even though it only won 4 legislative seats, the PDI-struggle strategy has been very good, as evidenced by the election votes that were more than in the previous period. On the other hand, the increasingly stringent quality of recruitment of legislative candidates is a solid foundation for the PDI-Struggle to produce legislative candidates who have electability and quality in fighting for people's rights and aspirations. Keywords: Political Strategy; PDIP; Legislative Member Electio

    Finding the middle ground: how kinetochores power chromosome congression

    Get PDF
    Genomic stability requires error-free chromosome segregation during mitosis. Chromosome congression to the spindle equator precedes chromosome segregation in anaphase and is a hallmark of metazoan mitosis. Here we review the current knowledge and concepts on the processes that underlie chromosome congression, including initial attachment to spindle microtubules, biorientation, and movements, from the perspective of the kinetochor

    Phylogenetic and structural analysis of centromeric DNA and kinetochore proteins

    Get PDF
    BACKGROUND: Kinetochores are large multi-protein structures that assemble on centromeric DNA (CEN DNA) and mediate the binding of chromosomes to microtubules. Comprising 125 base-pairs of CEN DNA and 70 or more protein components, Saccharomyces cerevisiae kinetochores are among the best understood. In contrast, most fungal, plant and animal cells assemble kinetochores on CENs that are longer and more complex, raising the question of whether kinetochore architecture has been conserved through evolution, despite considerable divergence in CEN sequence. RESULTS: Using computational approaches, ranging from sequence similarity searches to hidden Markov model-based modeling, we show that organisms with CENs resembling those in S. cerevisiae (point CENs) are very closely related and that all contain a set of 11 kinetochore proteins not found in organisms with complex CENs. Conversely, organisms with complex CENs (regional CENs) contain proteins seemingly absent from point-CEN organisms. However, at least three quarters of known kinetochore proteins are present in all fungi regardless of CEN organization. At least six of these proteins have previously unidentified human orthologs. When fungi and metazoa are compared, almost all have kinetochores constructed around Spc105 and three conserved multi-protein linker complexes (MIND, COMA, and the NDC80 complex). CONCLUSION: Our data suggest that critical structural features of kinetochores have been well conserved from yeast to man. Surprisingly, phylogenetic analysis reveals that human kinetochore proteins are as similar in sequence to their yeast counterparts as to presumptive Drosophila melanogaster or Caenorhabditis elegans orthologs. This finding is consistent with evidence that kinetochore proteins have evolved very rapidly relative to components of other complex cellular structures

    TRAIP is a regulator of the spindle assembly checkpoint.

    Get PDF
    Accurate chromosome segregation during mitosis is temporally and spatially coordinated by fidelity-monitoring checkpoint systems. Deficiencies in these checkpoint systems can lead to chromosome segregation errors and aneuploidy, and promote tumorigenesis. Here, we report that the TRAF-interacting protein (TRAIP), a ubiquitously expressed nucleolar E3 ubiquitin ligase important for cellular proliferation, is localized close to mitotic chromosomes. Its knockdown in HeLa cells by RNA interference (RNAi) decreased the time of early mitosis progression from nuclear envelope breakdown (NEB) to anaphase onset and increased the percentages of chromosome alignment defects in metaphase and lagging chromosomes in anaphase compared with those of control cells. The decrease in progression time was corrected by the expression of wild-type but not a ubiquitin-ligase-deficient form of TRAIP. TRAIP-depleted cells bypassed taxol-induced mitotic arrest and displayed significantly reduced kinetochore levels of MAD2 (also known as MAD2L1) but not of other spindle checkpoint proteins in the presence of nocodazole. These results imply that TRAIP regulates the spindle assembly checkpoint, MAD2 abundance at kinetochores and the accurate cellular distribution of chromosomes. The TRAIP ubiquitin ligase activity is functionally required for the spindle assembly checkpoint control

    Complete microtubule–kinetochore occupancy favours the segregation of merotelic attachments

    Get PDF
    Kinetochores are multi-protein complexes that power chromosome movements by tracking microtubules plus-ends in the mitotic spindle. Human kinetochores bind up to 20 microtubules, even though single microtubules can generate sufficient force to move chromosomes. Here, we show that high microtubule occupancy at kinetochores ensures robust chromosome segregation by providing a strong mechanical force that favours segregation of merotelic attachments during anaphase. Using low doses of the microtubules-targeting agent BAL27862 we reduce microtubule occupancy and observe that spindle morphology is unaffected and bi-oriented kinetochores can still oscillate with normal intra-kinetochore distances. Inter-kinetochore stretching is, however, dramatically reduced. The reduction in microtubule occupancy and inter-kinetochore stretching does not delay satisfaction of the spindle assembly checkpoint or induce microtubule detachment via Aurora-B kinase, which was so far thought to release microtubules from kinetochores under low stretching. Rather, partial microtubule occupancy slows down anaphase A and increases incidences of lagging chromosomes due to merotelically attached kinetochores

    Step-wise assembly, maturation and dynamic behavior of the human CENP-P/O/R/Q/U kinetochore sub-complex

    Get PDF
    Kinetochores are multi-protein megadalton assemblies that are required for attachment of microtubules to centromeres and, in turn, the segregation of chromosomes in mitosis. Kinetochore assembly is a cell cycle regulated multi-step process. The initial step occurs during interphase and involves loading of the 15-subunit constitutive centromere associated complex (CCAN), which contains a 5-subunit (CENP-P/O/R/Q/U) sub-complex. Here we show using a fluorescent three-hybrid (F3H) assay and fluorescence resonance energy transfer (FRET) in living mammalian cells that CENP-P/O/R/Q/U subunits exist in a tightly packed arrangement that involves multifold protein-protein interactions. This sub-complex is, however, not pre-assembled in the cytoplasm, but rather assembled on kinetochores through the step-wise recruitment of CENP-O/P heterodimers and the CENP-P, -O, -R, -Q and -U single protein units. SNAP-tag experiments and immuno-staining indicate that these loading events occur during S-phase in a manner similar to the nucleosome binding components of the CCAN, CENP-T/W/N. Furthermore, CENP-P/O/R/Q/U binding to the CCAN is largely mediated through interactions with the CENP-N binding protein CENP-L as well as CENP-K. Once assembled, CENP-P/O/R/Q/U exchanges slowly with the free nucleoplasmic pool indicating a low off-rate for individual CENP-P/O/R/Q/U subunits. Surprisingly, we then find that during late S-phase, following the kinetochore-binding step, both CENP-Q and -U but not -R undergo oligomerization. We propose that CENP-P/O/R/Q/U self-assembles on kinetochores with varying stoichiometry and undergoes a pre-mitotic maturation step that could be important for kinetochores switching into the correct conformation necessary for microtubule-attachment

    Kinetochore alignment within the metaphase plate is regulated by centromere stiffness and microtubule depolymerases

    Get PDF
    During mitosis in most eukaryotic cells, chromosomes align and form a metaphase plate halfway between the spindle poles, about which they exhibit oscillatory movement. These movements are accompanied by changes in the distance between sister kinetochores, commonly referred to as breathing. We developed a live cell imaging assay combined with computational image analysis to quantify the properties and dynamics of sister kinetochores in three dimensions. We show that baseline oscillation and breathing speeds in late prometaphase and metaphase are set by microtubule depolymerases, whereas oscillation and breathing periods depend on the stiffness of the mechanical linkage between sisters. Metaphase plates become thinner as cells progress toward anaphase as a result of reduced oscillation speed at a relatively constant oscillation period. The progressive slowdown of oscillation speed and its coupling to plate thickness depend nonlinearly on the stiffness of the mechanical linkage between sisters. We propose that metaphase plate formation and thinning require tight control of the state of the mechanical linkage between sisters mediated by centromeric chromatin and cohesion

    Human TPX2 is required for targeting Aurora-A kinase to the spindle

    Get PDF
    Aurora-A is a serine-threonine kinase implicated in the assembly and maintenance of the mitotic spindle. Here we show that human Aurora-A binds to TPX2, a prominent component of the spindle apparatus. TPX2 was identified by mass spectrometry as a major protein coimmunoprecipitating specifically with Aurora-A from mitotic HeLa cell extracts. Conversely, Aurora-A could be detected in TPX2 immunoprecipitates. This indicates that subpopulations of these two proteins undergo complex formation in vivo. Binding studies demonstrated that the NH2 terminus of TPX2 can directly interact with the COOH-terminal catalytic domain of Aurora-A. Although kinase activity was not required for this interaction, TPX2 was readily phosphorylated by Aurora-A. Upon siRNA-mediated elimination of TPX2 from cells, the association of Aurora-A with the spindle microtubules was abolished, although its association with spindle poles was unaffected. Conversely, depletion of Aurora-A by siRNA had no detectable influence on the localization of TPX2. We propose that human TPX2 is required for targeting Aurora-A kinase to the spindle apparatus. In turn, Aurora-A might regulate the function of TPX2 during spindle assembly

    A dual role for Bub1 in the spindle checkpoint and chromosome congression

    Full text link

    Bub1 regulates chromosome segregation in a kinetochore-independent manner

    Get PDF
    The kinetochore-bound protein kinase Bub1 performs two crucial functions during mitosis: it is essential for spindle checkpoint signaling and for correct chromosome alignment. Interestingly, Bub1 mutations are found in cancer tissues and cancer cell lines. Using an isogenic RNA interference complementation system in transformed HeLa cells and untransformed RPE1 cells, we investigate the effect of structural Bub1 mutants on chromosome segregation. We demonstrate that Bub1 regulates mitosis through the same mechanisms in both cell lines, suggesting a common regulatory network. Surprisingly, Bub1 can regulate chromosome segregation in a kinetochore-independent manner, albeit at lower efficiency. Its kinase activity is crucial for chromosome alignment but plays only a minor role in spindle checkpoint signaling. We also identify a novel conserved motif within Bub1 (amino acids 458–476) that is essential for spindle checkpoint signaling but does not regulate chromosome alignment, and we show that several cancer-related Bub1 mutants impair chromosome segregation, suggesting a possible link to tumorigenesis
    corecore