Ontology highlight
ABSTRACT:
PROVIDER: PRJNA637024 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR11916459_1.fastq.gz | Fastqsanger.gz | |||
| SRR11916459_2.fastq.gz | Fastqsanger.gz | |||
| SRR11916460_1.fastq.gz | Fastqsanger.gz | |||
| SRR11916460_2.fastq.gz | Fastqsanger.gz |
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Project description:Eukaryotic cell proliferation requires chromosome replication and precise segregation to ensure daughter cells have identical genomic copies. The genus Plasmodium, the causative agent of malaria, has developed remarkable characteristic of nuclear division throughout its lifecycle to meet some peculiar and unique challenges of DNA replication and chromosome segregation. The parasite undergoes atypical endomitosis and endoreduplication with an intact nuclear membrane and intranuclear mitotic spindle. To understand diverse modes of cell division in Plasmodium we have studied the behaviour and composition of a key part of the mitotic apparatus, the outer kinetochore Ndc80 complex that attaches the centromere of chromosomes to the microtubules of the mitotic spindle. Using Ndc80 live-cell imaging in Plasmodium berghei we observe dynamic changes throughout proliferative life-stages including highly unusual kinetochore arrangements in sexual stages of the parasite. Furthermore, we identify a divergent Spc24 component of Ndc80 complex, previously thought to be missing, and completing a canonical, albeit unusual, Ndc80 complex structure. Altogether our studies reveal the kinetochore as an ideal starting point towards understanding non-canonical modes of chromosome segregation and cell division in Plasmodium.
2020-06-09 | PXD017619 | Pride
Project description:The Aurora family of kinases orchestrates chromosome segregation and cytokinesis during cell division, with precise spatiotemporal regulation of its catalytic activities by distinct protein scaffolds. Plasmodium spp., the causative agents of malaria, are unicellular eukaryotes with three unique and highly divergent aurora-related kinases (ARK1-3) that are essential for asexual cellular proliferation, but lack most canonical scaffolds/activators. Here we investigate the role of ARK2 during sexual proliferation of the rodent malaria Plasmodium berghei, using a combination of super-resolution microscopy, mass spectrometry, and live-cell fluorescence imaging. We find that ARK2 is primarily located at spindle apparatus microtubules in the vicinity of kinetochores during both mitosis and meiosis. Interactomic and co-localisation studies reveal several putative ARK2-associated interactors including the microtubule plus end-binding protein EB1, together with MISFIT and Myosin-K, but no conserved eukaryotic scaffold proteins. Gene function studies indicate that ARK2 and EB1 are complementary in driving endomitotic division and thereby parasite transmission through the mosquito. This discovery underlines the flexibility of molecular networks to rewire and drive unconventional mechanisms of chromosome segregation in the malaria parasite.
2023-08-15 | PXD043164 | Pride
Project description:Mitosis is an important process in the cell cycle required for cells to divide. Never in mitosis (NIMA)-like kinases (NEKs) are regulators of mitotic functions in diverse organisms. Plasmodium spp, the causative agent of malaria is a divergent unicellular haploid eukaryote with some unusual features in terms of its mitotic and nuclear division cycle that presumably facilitate proliferation in varied environments. For example, during the sexual stage of male gametogenesis that occurs within the mosquito host, an atypical rapid closed endomitosis is observed. Three rounds of genome replication from 1N to 8N and successive cycles of multiple spindle formation and chromosome segregation occur within eight minutes followed by karyokinesis to generate haploid gametes. Our previous Plasmodium berghei kinome screen identified four Nek genes, of which two, NEK2 and NEK4, are required for meiosis. NEK1 is likely to be essential for mitosis in asexual blood stage schizogony in the vertebrate host, but its function during male gametogenesis is unknown. Here, we study NEK1 location and function, using live cell imaging, ultrastructure expansion microscopy (U-ExM) and electron microscopy, together with conditional gene knockdown and proteomic approaches. We report spatiotemporal NEK1 location in real-time, coordinated with microtubule organising centre (MTOC) dynamics during the unusual mitoses at various stages of the Plasmodium spp. life cycle. Knockdown studies reveal NEK1 to be an essential component of the MTOC in male cell differentiation, associated with rapid mitosis, spindle formation and kinetochore attachment. These data suggest that Plasmodium berghei NEK1 kinase is an important component of MTOC organisation and essential regulator of chromosome segregation during male gamete formation.
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Project description:Chromosome segregation in Streptococcus pneumoniae
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Project description:Histone variants are key components of the epigenetic code and evolved to perform specific functions in transcriptional regulation, DNA repair, chromosome segregation and other fundamental processes. H2B.Z is a rare, apicomplexan-specific variant of histone H2B. Here we show that in Plasmodium falciparum H2B.Z localises to euchromatic intergenic regions throughout intraerythrocytic development and together with H2A.Z forms a double-variant nucleosomes subtype. These nucleosomes are enriched in promoters over 3’ intergenic regions and their occupancy generally correlates with the strength of the promoter, but not with its temporal activity. Remarkably, H2B.Z occupancy levels exhibit a clear correlation with the base-composition of the underlying DNA, raising the intriguing possibility that the extreme AT-content of the intergenic regions within the Plasmodium genome might be instructive for histone variant deposition. In summary, our data shows that the H2A.Z/H2B.Z double-variant nucleosome demarcates putative regulatory regions of the P. falciparum epigenome and likely provides a scaffold for dynamic regulation of gene expression in this deadly human pathogen. Genome-wide localization of H2B.Z has been studied at three stages of intraerythrocytic development by Illumina sequencing of chromatin-immunoprecipitated and input DNA.
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Project description:Histone variants are key components of the epigenetic code and evolved to perform specific functions in transcriptional regulation, DNA repair, chromosome segregation and other fundamental processes. H2B.Z is a rare, apicomplexan-specific variant of histone H2B. Here we show that in Plasmodium falciparum H2B.Z localises to euchromatic intergenic regions throughout intraerythrocytic development and together with H2A.Z forms a double-variant nucleosomes subtype. These nucleosomes are enriched in promoters over 3’ intergenic regions and their occupancy generally correlates with the strength of the promoter, but not with its temporal activity. Remarkably, H2B.Z occupancy levels exhibit a clear correlation with the base-composition of the underlying DNA, raising the intriguing possibility that the extreme AT-content of the intergenic regions within the Plasmodium genome might be instructive for histone variant deposition. In summary, our data shows that the H2A.Z/H2B.Z double-variant nucleosome demarcates putative regulatory regions of the P. falciparum epigenome and likely provides a scaffold for dynamic regulation of gene expression in this deadly human pathogen.
2013-03-05 | GSE39702 | GEO
Project description:Alternative RNA splicing can generate distinct protein isoforms to allow for the differential control of cell processes across cell types. The chromosome segregation and cell division programs associated with somatic mitosis and germline meiosis display dramatic differences such as kinetochore orientation, cohesin removal, or the presence of a gap phase. These changes in chromosome segregation require alterations to the established cell division machinery. However, it remains unclear what aspects of kinetochore function and its regulatory control differ between the mitotic and meiotic cell divisions to rewire these core processes. Additionally, the alternative splice isoforms that differentially modulate distinct cell division programs have remained elusive. Here, we demonstrate that mammalian germ cells express an alternative mRNA splice isoform for the kinetochore component, DSN1, a subunit of the MIS12 complex that links the centromeres to spindle microtubules during chromosome segregation. This germline DSN1 isoform bypasses the requirement for Aurora kinase phosphorylation for its centromere localization due to the absence of a key regulatory region allowing DSN1 to display persistent centromere localization. Expression of the germline DSN1 isoform in somatic cells results in constitutive kinetochore localization, chromosome segregation errors, and growth defects, providing an explanation for its tight cell type-specific expression. Reciprocally, precisely eliminating expression of the germline-specific DSN1 splice isoform in mouse models disrupts oocyte maturation and early embryonic divisions coupled with a reduction in fertility. Together, this work identifies a germline-specific splice isoform for a chromosome segregation component and implicates its role in mammalian fertility.
2025-02-07 | MSV000097075 | MassIVE
Project description:Retrotransposons have invaded eukaryotic centromeres in cycles of repeat expansion and purging, but the function of centromeric retrotransposons, if any, has remained unclear. In Arabidopsis, centromeric ATHILA retrotransposons give rise to epigenetically activated short interfering RNAs (easiRNAs) in mutants in DECREASE IN DNA METHYLATION1 (DDM1), which promote histone H3 lysine-9 di-methylation (H3K9me2). Here, we show that mutants which lose both DDM1 and RNA dependent RNA polymerase (RdRP) have pleiotropic developmental defects and mis-segregation of chromosome 5 during mitosis. Fertility defects are epigenetically inherited with the centromeric region of chromosome 5, and can be rescued by directing artificial small RNAs to a single family of ATHILA5 retrotransposons specifically embedded within this centromeric region. easiRNAs and H3K9me2 promote pericentromeric condensation, chromosome cohesion and proper chromosome segregation in mitosis. Insertion of ATHILA silences transcription, while simultaneously making centromere function dependent on retrotransposon small RNAs, promoting the selfish survival and spread of centromeric retrotransposons. Parallels are made with the fission yeast S. pombe, where chromosome segregation depends on RNAi, and with humans, where chromosome segregation depends on both RNAi and HELLSDDM1.
2022-10-24 | GSE132005 | GEO
Project description:Replication and segregation are the two main processes that maintain chromosomes in growing cells. In bacteria, replication and transcription have been proposed to provide motive force in chromosome segregation. Recently, ParB2, a segregation protein, encoded by V. cholerae chromosome II (chrII) was also found to influence chrII replication. V. cholerae chrII replication is primarily controlled by its specific initiator protein, RctB. Here, we have screened for ParB2 and RctB binding sites using a genome-wide DNA binding analysis (ChIP-chip). We report the identification of a new region containing additional RctB and ParB2 binding sites, and suggest the mechanisms to coordinate replication initiation with segregation of chromosomes.
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