Project description:Purpose: The ultimate goal of this study is the identification of transcription elongation-related chromatin remodeler and its in vivo mechanism in fission yeast through Next-generation sequencing (NGS) based ChIP-seq technique. Methods: Every ChIP-seq cells were grown up to mid-log phase and harvested after final 1% formaldehyde fixation and 125mM glycine quencing. Cells were harvested by centrifugation at 4 Celcius degrees and the cell pellets were washed by 15mL of pH7.5 TBS buffer per a conical tube. ChIP cells were disrupted by glass bead vortexing in ChIP lysis buffer and sonicated by Sonic Dismembrator Model 500, Fisher Scientific. Debris of the sonicate was excluded by centrifugation by 14,800rpm at 4 Celcius degree. IP samples were aliqouted from the sonicate and immunoprecipiated by proper amount of antibody and protein A/G beads, washed by ChIP lysis buffer for over-night at 4 Celcius degrees. IP samples were washed and eluted by proper buffers in Sigmaprep spin column. Proteins in both IP and input samples were degraded by 2hr 30ug proteinase K rxn and de-crosslinked at 65 Celcius degrees for at least 8hrs. The IP and input DNA were eluted by Quiagen PCR purification kit. Results: RNAPII and factor ChIP-seq in various mutants of chromatin remodelers showed that FUN30 family promotes transcription at gene coding regions. RNAPII ChIP-seq in fft3Δ, spt16-1 and fft3Δspt16-1 demonstrated that RNAPII regulation function of Fft3 is largely overlapped with that of Spt16. Histone H3 ChIP-seq results in fft3Δ and spt16-18 demonstrated that Fft3 is major chromatin remodeler to promote nucleosome turnover through nucleosome disassembly. Finally, histone H3 and RNAPII ChIP-seq in fft3Δ, H3/H4DD and fft3Δ H3/H4DD were showed that Fft3 facilitates RNAPII elongation at ORF regions through nucleosome barrier regulation. Conclusions: Fun30-Fft3 is major chromatin remodeler to facilitate RNAPII elongation by nucleosome disassembly-driven nucleosome barrier alleviation in fission yeast.
Project description:Hrp3_Purification from Schizosaccharomyces pombe 972h- Eukaryotic genome is composed of repeating units of nucleosomes to form chromatin arrays. A canonical gene is marked by nucleosome free region (NFR) at its 5’ end followed by uniformly spaced arrays of nucleosomes. In fission yeast we show both biochemically and in vivo that both Hrp1 and Hrp3 are key determinants of uniform spacing of genic arrays.
Project description:In eukaryotic cells, local chromatin structure and chromatin organization in the nucleus both influence transcriptional regulation. At the local level, the Fun30 chromatin remodeler Fft3 is essential for maintaining proper chromatin structure at centromeres and subtelomeres in fission yeast. Using genome-wide mapping and live cell imaging, we show that this role is linked to controlling nuclear organization of its targets. In fft3M-NM-^T cells, subtelomeres lose their association with the LEM domain protein Man1 at the nuclear periphery and move to the interior of the nucleus. Furthermore, genes in these domains are upregulated and active chromatin marks increase. Fft3 is also enriched at retrotransposon-derived long terminal repeat (LTR) elements at the borders of subtelomeres and at tRNA genes. In cells lacking Fft3, these sites lose their peripheral positioning and show reduced nucleosome occupancy. We propose that Fft3 has a global role in mediating association between specific chromatin domains and components of the nuclear envelope by maintaining chromatin structure required for anchoring DNA insulators to nuclear pores. For MNase samples, duplicate mutant mononucleosome fractions were compared with duplicate WT mononucleosomes.
Project description:In eukaryotic cells, local chromatin structure and chromatin organization in the nucleus both influence transcriptional regulation. At the local level, the Fun30 chromatin remodeler Fft3 is essential for maintaining proper chromatin structure at centromeres and subtelomeres in fission yeast. Using genome-wide mapping and live cell imaging, we show that this role is linked to controlling nuclear organization of its targets. In fft3Δ cells, subtelomeres lose their association with the LEM domain protein Man1 at the nuclear periphery and move to the interior of the nucleus. Furthermore, genes in these domains are upregulated and active chromatin marks increase. Fft3 is also enriched at retrotransposon-derived long terminal repeat (LTR) elements at the borders of subtelomeres and at tRNA genes. In cells lacking Fft3, these sites lose their peripheral positioning and show reduced nucleosome occupancy. We propose that Fft3 has a global role in mediating association between specific chromatin domains and components of the nuclear envelope by maintaining chromatin structure required for anchoring DNA insulators to nuclear pores.
Project description:In eukaryotic cells, local chromatin structure and chromatin organization in the nucleus both influence transcriptional regulation. At the local level, the Fun30 chromatin remodeler Fft3 is essential for maintaining proper chromatin structure at centromeres and subtelomeres in fission yeast. Using genome-wide mapping and live cell imaging, we show that this role is linked to controlling nuclear organization of its targets. In fft3Δ cells, subtelomeres lose their association with the LEM domain protein Man1 at the nuclear periphery and move to the interior of the nucleus. Furthermore, genes in these domains are upregulated and active chromatin marks increase. Fft3 is also enriched at retrotransposon-derived long terminal repeat (LTR) elements at the borders of subtelomeres and at tRNA genes. In cells lacking Fft3, these sites lose their peripheral positioning and show reduced nucleosome occupancy. We propose that Fft3 has a global role in mediating association between specific chromatin domains and components of the nuclear envelope by maintaining chromatin structure required for anchoring DNA insulators to nuclear pores.
Project description:The chromosomes of eukaryotes are organized into structurally and functionally discrete domains. This implies the presence of insulator elements that separate adjacent domains, allowing them to maintain different chromatin structures. We show that the Fun30 chromatin remodeler, Fft3, is essential for maintaining a proper chromatin structure at centromeres and subtelomeres. Fft3 is localized to insulator elements and inhibits euchromatin assembly in silent chromatin domains. In its absence, euchromatic histone modifications and histone variants invade centromeres and subtelomeres, causing a mis-regulation of gene expression and severe chromosome segregation defects. Our data strongly suggest that Fft3 controls the identity of chromatin domains by protecting these regions from euchromatin assembly.
Project description:In eukaryotic cells, local chromatin structure and chromatin organization in the nucleus both influence transcriptional regulation. At the local level, the Fun30 chromatin remodeler Fft3 is essential for maintaining proper chromatin structure at centromeres and subtelomeres in fission yeast. Using genome-wide mapping and live cell imaging, we show that this role is linked to controlling nuclear organization of its targets. In fft3M-NM-^T cells, subtelomeres lose their association with the LEM domain protein Man1 at the nuclear periphery and move to the interior of the nucleus. Furthermore, genes in these domains are upregulated and active chromatin marks increase. Fft3 is also enriched at retrotransposon-derived long terminal repeat (LTR) elements at the borders of subtelomeres and at tRNA genes. In cells lacking Fft3, these sites lose their peripheral positioning and show reduced nucleosome occupancy. We propose that Fft3 has a global role in mediating association between specific chromatin domains and components of the nuclear envelope by maintaining chromatin structure required for anchoring DNA insulators to nuclear pores. For DamID samples, we recorded methylation levels for Dam fusion proteins and compared them to Dam-only control samples. For ChIP samples, we compared immuno-precipitated DNA to mock or input controls.
Project description:H3K9me2 profiles and Fft3 occupancy in fission yeast. Heterochromatin can be epigenetically inherited in cis, leading to stable maintenance of gene expression states. However, the mechanisms underlying heterochromatin inheritance remain unclear. Here we identify Fft3, a homolog of the mammalian SMARCAD1 Snf2 chromatin remodeler, as a factor uniquely required for heterochromatin inheritance, rather than for de novo assembly. Importantly, we find that Fft3 bound to heterochromatic loci suppresses turnover of parental histones and is critical for the epigenetic transmission of heterochromatin in cycling cells. Surprisingly, Fft3 also localizes to several euchromatic loci where it is required for proper replication progression. Fft3 promotes nucleosome stability at these loci to prevent R-loop formation that can impede replication machinery. Strikingly, overexpression of the Clr4/Suv39h methyltransferase, which is also required for efficient replication through these loci, suppresses phenotypes associated with the loss of Fft3. Thus, we find that Fft3 promotes nucleosome stability to facilitate heterochromatin inheritance and also acts in parallel to Clr4 ensure proper replication of euchromatic regions.
Project description:BrdU profiling of replication activity in synchronous culture of fission yeast. Heterochromatin can be epigenetically inherited in cis, leading to stable maintenance of gene expression states. However, the mechanisms underlying heterochromatin inheritance remain unclear. Here we identify Fft3, a homolog of the mammalian SMARCAD1 Snf2 chromatin remodeler, as a factor uniquely required for heterochromatin inheritance, rather than for de novo assembly. Importantly, we find that Fft3 bound to heterochromatic loci suppresses turnover of parental histones and is critical for the epigenetic transmission of heterochromatin in cycling cells. Surprisingly, Fft3 also localizes to several euchromatic loci where it is required for proper replication progression. Fft3 promotes nucleosome stability at these loci to prevent R-loop formation that can impede replication machinery. Strikingly, overexpression of the Clr4/Suv39h methyltransferase, which is also required for efficient replication through these loci, suppresses phenotypes associated with the loss of Fft3. Thus, we find that Fft3 promotes nucleosome stability to facilitate heterochromatin inheritance and also acts in parallel to Clr4 ensure proper replication of euchromatic regions.
Project description:BrdU profiling of replication activity in hydroxyurea treated synchronous culture of fission yeast. Heterochromatin can be epigenetically inherited in cis, leading to stable maintenance of gene expression states. However, the mechanisms underlying heterochromatin inheritance remain unclear. Here we identify Fft3, a homolog of the mammalian SMARCAD1 Snf2 chromatin remodeler, as a factor uniquely required for heterochromatin inheritance, rather than for de novo assembly. Importantly, we find that Fft3 bound to heterochromatic loci suppresses turnover of parental histones and is critical for the epigenetic transmission of heterochromatin in cycling cells. Surprisingly, Fft3 also localizes to several euchromatic loci where it is required for proper replication progression. Fft3 promotes nucleosome stability at these loci to prevent R-loop formation that can impede replication machinery. Strikingly, overexpression of the Clr4/Suv39h methyltransferase, which is also required for efficient replication through these loci, suppresses phenotypes associated with the loss of Fft3. Thus, we find that Fft3 promotes nucleosome stability to facilitate heterochromatin inheritance and also acts in parallel to Clr4 ensure proper replication of euchromatic regions.