Centromeric chromatin in Koala
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ABSTRACT:
PROVIDER: PRJNA436016 | ENA |
REPOSITORIES: ENA
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Project description:We report high throughput sequencing of DNA associated with centromeric chromatin in the koala genome.
2018-04-26 | GSE111153 | GEO
Project description:The centromere is the genetic locus that organizes the proteinaceous kinetochore and is responsible for attachment of the chromosome to the spindle at mitosis and meiosis. In most eukaryotes, the centromere consists of highly repetitive DNA sequences that are occupied by nucleosomes containing the CenH3 histone variant, whereas in budding yeast, an ~120-bp Centromere DNA Element (CDE) that is sufficient for centromere function is occupied by a single right-handed CenH3 (Cse4) nucleosome. However, these in vivo observations are inconsistent with in vitro evidence for left-handed octameric CenH3 nucleosomes. To help resolve these inconsistencies, we characterized yeast centromeric chromatin at single base-pair resolution. Intact particles containing both Cse4 and H2A are precisely protected from micrococcal nuclease over the entire CDE of all 16 yeast centromeres in both solubilized chromatin and the insoluble kinetochore. Small DNA-binding proteins protect CDEI and CDEIII and delimit the centromeric nucleosome to the ~80-bp CDEII, only enough for a single DNA wrap. As expected for a tripartite organization of centromeric chromatin, loss of Cbf1 protein, which binds to CDEI, both reduces the size of the centromere-protected region and shifts its location towards CDEIII. Surprisingly, Cse4 overproduction caused genome-wide misincorporation of non-functional CenH3-containing nucleosomes that protect ~135 base pairs and are preferentially enriched at sites of high nucleosome turnover. Our detection of two forms of CenH3 nucleosomes in the yeast genome, a singly wrapped particle at the functional centromere and octamer-sized particles on chromosome arms, reconcile seemingly conflicting in vivo and in vitro observations. We used micrococcal nuclease mapping, chromatin immunoprecipitation and paired-end sequencing to determine the structure of yeast centromeres at single base-pair resolution.
2011-12-07 | E-GEOD-28298 | biostudies-arrayexpress
Project description:Functional centromeres are essential for proper cell division. Centromeres are established largely by epigenetic processes resulting in incorporation of the histone H3 variant CENP-A. Here, we demonstrate the direct involvement of H2B monoubiquitination, mediated by RNF20 in humans or Brl1 in Schizosaccharomyces pombe, in centromeric chromatin maintenance. Monoubiquinated H2B (H2Bub1) is needed for this maintenance, promoting noncoding transcription, centromere integrity and accurate chromosomal segregation. A transient pulse of centromeric H2Bub1 leads to RNA polymerase II–mediated transcription of the centromere’s central domain, coupled to decreased H3 stability. H2Bub1-deficient cells have centromere cores that, despite their intact centromeric heterochromatin barriers, exhibit characteristics of heterochromatin, such as silencing histone modifications, reduced nucleosome turnover and reduced levels of transcription. In the H2Bub1-deficient cells, centromere functionality is hampered, thus resulting in unequal chromosome segregation. Therefore, centromeric H2Bub1 is essential for maintaining active centromeric chromatin.
2014-01-29 | GSE49874 | GEO
Project description:We examined genome-wide patterns of DNA methylation from whole genome DNA methylation maps of five tissues (brain, kidney, lung, skeletal muscle, and pancreas) from one male koala and one female koala (Phascolarctos cinereus), and present the first whole genome, multi-tissue “methylome atlas” with information on tissue- and sex-specific variation of DNA methylation for a marsupial.
2021-02-27 | GSE149600 | GEO
Project description:Centromeres of most eukaryotes are multi-megabase arrays of satellite DNA that assemble proteinaceous kinetochores to facilitate faithful chromosome segregation. However, the nature of the chromatin landscape at centromeres remains unclear, in part due to the difficulty of isolating intact centromeric chromatin rendered insoluble by megadalton-size kinetochore protein complexes. To address this challenge we combined classical salt fractionation with chromatin immunoprecipitation to recover human centromeric chromatin under native conditions. We found that >85% of the total centromeric chromatin is insoluble under conditions typically used for native chromatin extraction. To map both soluble and insoluble chromatin in situ, we combined CUT&RUN, a targeted nuclease method, with salt fractionation. Using this approach, we found that the strength of Centromere Protein B (CENP-B) binding and the density of CENP-B motifs corresponds to the occupancy of Constitutive Centromere-Assocated Network (CCAN) complexes bound to α-satellite arrays. We also observed unexpected structural variations of CENP-A-containing complexes on different α-satellite dimeric units within highly homogenous arrays. Our results suggest that slight α-satellite sequence differences controls the structure and occupancy of the associated centromeric chromatin complex.
2018-01-31 | GSE104805 | GEO
Project description:The centromere is the genetic locus that organizes the proteinaceous kinetochore and is responsible for attachment of the chromosome to the spindle at mitosis and meiosis. In most eukaryotes, the centromere consists of highly repetitive DNA sequences that are occupied by nucleosomes containing the CenH3 histone variant, whereas in budding yeast, an ~120-bp Centromere DNA Element (CDE) that is sufficient for centromere function is occupied by a single right-handed CenH3 (Cse4) nucleosome. However, these in vivo observations are inconsistent with in vitro evidence for left-handed octameric CenH3 nucleosomes. To help resolve these inconsistencies, we characterized yeast centromeric chromatin at single base-pair resolution. Intact particles containing both Cse4 and H2A are precisely protected from micrococcal nuclease over the entire CDE of all 16 yeast centromeres in both solubilized chromatin and the insoluble kinetochore. Small DNA-binding proteins protect CDEI and CDEIII and delimit the centromeric nucleosome to the ~80-bp CDEII, only enough for a single DNA wrap. As expected for a tripartite organization of centromeric chromatin, loss of Cbf1 protein, which binds to CDEI, both reduces the size of the centromere-protected region and shifts its location towards CDEIII. Surprisingly, Cse4 overproduction caused genome-wide misincorporation of non-functional CenH3-containing nucleosomes that protect ~135 base pairs and are preferentially enriched at sites of high nucleosome turnover. Our detection of two forms of CenH3 nucleosomes in the yeast genome, a singly wrapped particle at the functional centromere and octamer-sized particles on chromosome arms, reconcile seemingly conflicting in vivo and in vitro observations.
2011-12-07 | GSE28298 | GEO
Project description:The aims of this study were to investigate the proteome of koala (Phascolarctos cinereus) spermatozoa and that of the prostatic bodies with which they form intimate contact at the moment of ejaculation. For this purpose, spermatozoa and prostatic bodies were obtained from four adult male koala by electroejaculation and analysed by high performance liquid chromatography coupled to a mass spectrometer. This strategy successfully identified and 744 koala sperm and 1,297 prostatic body proteins, which were subsequently attributed to 482 and 776 unique gene products, respectively. Gene ontology curation of the koala sperm proteome revealed an abundance of proteins mapping to the canonical sirtuin and 14-3-3 signalling pathways. By contrast, protein ubiquitination and unfolding protein response pathways dominated the equivalent analysis of proteins uniquely identified in koala prostatic bodies. In terms of functional annotation, koala sperm proteins commonly mapped to the categories of cellular compromise/inflammatory response, whilst those of the prostatic body revealed an over-representation of molecular chaperone and stress-related proteins associated with cell survival. Cross-species comparisons demonstrated that the koala sperm proteome displays greater conservation with that of eutherians (human; 93%) as opposed to reptile (crocodile; 39%) and avian (rooster; 27%) spermatozoa. Similarly, koala prostatic body proteins also presented a relatively high degree of overlap (70%) with those identified in sub-populations of large human seminal plasma extracellular vesicles. Together, this work contributes our overall understanding of the core sperm proteome and has identified candidate markers that may contribute to the exceptional longevity of koala spermatozoa during ex vivo storage.
2021-08-23 | PXD024250 | Pride
Project description:Functional centromeres are essential for proper cell division. Centromeres are established largely by epigenetic processes resulting in incorporation of the histone H3 variant CENP-A. Here, we demonstrate the direct involvement of H2B monoubiquitination, mediated by RNF20 in humans or Brl1 in Schizosaccharomyces pombe, in centromeric chromatin maintenance. Monoubiquinated H2B (H2Bub1) is needed for this maintenance, promoting noncoding transcription, centromere integrity and accurate chromosomal segregation. A transient pulse of centromeric H2Bub1 leads to RNA polymerase IIM-bM-^@M-^Smediated transcription of the centromereM-bM-^@M-^Ys central domain, coupled to decreased H3 stability. H2Bub1-deficient cells have centromere cores that, despite their intact centromeric heterochromatin barriers, exhibit characteristics of heterochromatin, such as silencing histone modifications, reduced nucleosome turnover and reduced levels of transcription. In the H2Bub1-deficient cells, centromere functionality is hampered, thus resulting in unequal chromosome segregation. Therefore, centromeric H2Bub1 is essential for maintaining active centromeric chromatin. ChIP: In total 17 samples; 15 ChIP DNA files (7 different conditions) 2 Input files. Cnp1_WT_input.bar (antibody against Cnp1 in strains Hu303, Hu29 (WT) (Cnp1_Hu303.CEL, AS_10.CEL) vs input (JW_1.CEL, JW_2_2.CEL)); Cnp1_Hu2640_WT.bar (antibody against Cnp1 in strain Hu2640 (htb1K119R) (Cnp1_Hu2640_A.CEL, Cnp1_Hu2640_B.CEL) vs strains Hu303, Hu29 (WT) (Cnp1_Hu303.CEL, AS_10.CEL)); Cnp1_Hu2640_input.bar (antibody against Cnp1 in strain Hu2640 (htb1K119R) (Cnp1_Hu2640_A.CEL, Cnp1_Hu2640_B.CEL) vs input (JW_1.CEL, JW_2_2.CEL)); H2Bub1_Hu303_input.bar (antibody against H2Bub1 in strain Hu303 (WT) (H2Bub1_Hu303_A.CEL, H2Bub1_Hu303_B.CEL) vs input (JW_1.CEL, JW_2_2.CEL)); H3_WT_input.bar (antibody against H3 in strains Hu303, Hu29 (WT) (H3_Hu303.CEL, As_12.CEL) vs input (JW_1.CEL, JW_2_2.CEL); H3_Hu2640_WT.bar (antibody against H3 in strain Hu2640 (htb1K119R) (H3_Hu2640_A.CEL, H3_Hu2640_B.CEL, H3_Hu2640_C.CEL) vs strains Hu303, Hu29 (WT) (H3_Hu303.CEL, AS_12.CEL)); H3_Hu2640_input.bar (antibody against H3 in strain Hu2640 (htb1K119R) (H3_Hu2640_A.CEL, H3_Hu2640_B.CEL, H3_Hu2640_C.CEL) vs input (JW_1.CEL, JW_2_2.CEL)); H3K9me2_Hu303_input.bar (antibody against H3K9me2 in strains Hu303, Hu29 (WT) (H3K9me2_Hu303.CEL, AS_6.CEL) vs input (JW_1.CEL, JW_2_2.CEL)); H3k9me2_Hu2640_Hu303.bar (antibody against H3K9me2 in strain Hu2640 (htb1K119R) (H3K9me2_Hu2640_A.CEL, H3K9me2_Hu2640_B.CEL) vs strain Hu303, Hu29 (WT) (H3K9me2_Hu303.CEL, AS_6.CEL)); H3K9me2_Hu2640_input.bar (antibody against H3K9me2 in strain Hu2640 (htb1K119R) (H3K9me2_Hu2640_A.CEL, H3K9me2_Hu2640_B.CEL) vs input (JW_1.CEL, JW_2_2.CEL)). RNA: 4 RNA samples: 2 replicates of WT RNA (RNA_Hu303_A.CEL, RNA_Hu303_B.CEL) and 2 replicates of htb1-K119R RNA (RNA_Hu2640_A.CEL, RNA_Hu2640_B.CEL).
2014-01-29 | E-GEOD-49874 | biostudies-arrayexpress
Project description:Chromatin Immunoprecipitation of centromeric protein A, histone3 K4 and K9 modifications, HP1a and HP1g
2010-02-27 | E-TABM-705 | biostudies-arrayexpress
Project description:In most plants, centromeric DNA contains highly repetitive sequences, including tandem repeats and retrotransposons; however, the roles of these sequences in the structure and function of the centromere are unclear. Here, we found that retrotransposon-derived back-spliced RNA can bind to the centromere through R-loops and regulate the formation of centromeric chromatin loops. Multiple RNA sequences from centromeric retrotransposons (CRMs) were enriched in maize (Zea mays) centromeres and back spliced RNA from CRM1 were detected. We identified three types of circular CRM1 RNAs with the same back-splicing site based on the back-spliced sequences. These circular RNAs bound to the centromere through R-loops. Two R-loop sites inside a single circular RNA promoted the formation of chromatin loops in CRM1 regions. When RNAi was used to target the back-spliced site of the circular CRM1 RNAs, the levels of R-loops and chromatin loops formed by these circular RNAs decreased, while the levels of R-loops produced by linear RNAs with similar binding sites increased. Linear RNAs with only one R-loop site could not promote chromatin loop formation. Higher levels of R-loops and lower levels of chromatin loops in the CRM1 regions of RNAi plants led to a reduced localization of the centromeric H3 variant (CENH3). Our work reveals that centromeric chromatin organization by circular CRM1 RNAs via R-loops and chromatin loops. R-loops are integral components of centromeric chromatin. Proper centromere structure is essential for CENH3 localization. CRM1 elements may have helped to build a suitable chromatin environment during centromere evolution.
2020-01-01 | GSE137701 | GEO