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ABSTRACT:
PROVIDER: PRJNA422879 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:During transcription the nascent RNA can invade the DNA template, forming extended RNA-DNA duplexes (R-loops). Here we employ ChIP-seq in strains expressing or lacking RNase H to map targets of RNase H activity throughout budding yeast genome. In wild-type strains, R-loops were readily detected over the 35S rDNA region transcribed by Pol I and over the 5S rDNA transcribed by Pol III. In strains lacking RNase H activity, R-loops were elevated over other Pol III genes notably tRNAs, SCR1 and U6 snRNA, and were also associated with the cDNAs of endogenous TY1 retrotransposons, which showed increased rates of mobility to the 5?-flanking regions of tRNA genes. Unexpectedly, R-loops were also associated with mitochondrial genes in the absence of RNase H1, but not of RNase H2. Finally, R-loops were detected on highly expressed protein-coding genes in the wild-type, notably over the second exon of spliced ribosomal protein genes. ChIP-seq of RNA-DNA hybrids using antibody S9.6
2014-11-03 | E-GEOD-53420 | biostudies-arrayexpress
Project description:Over 2000 publicly accessible human and mouse ChIP-Seq datasets for about 250 Transcription Factors and chromatin complexes from various databases (ENCODE, GEO) were mapped to custom-made human and mouse genomes containing a reference rDNA sequence of the appropriate species (Genbank U13369.1 for human, BK000964.3 for mouse). The read mapping density across the rDNA sequence was then extracted and normalized to the median in that dataset. Unbiased clustering and analysis, followed by curation, was performed to identify high-confidence patterns of rDNA occupancy for numerous hematopoietic TFs and TF families at canonical TF motif sequences. ************************ Data processing steps: FASTQs were trimmed using Trimmomatic with the following parameters: LEADING:3 TRAILING:3 SLIDINGWINDOW:4:15 MINLEN:30 Reads were mapped to customized genomes (containing additional rDNA sequence) using Bowtie2 using the following parameter: -X 2000 Read density across the rDNA sequence was extracted using igvtools ************************
2022-01-15 | GSE191272 | GEO
Project description:In eukaryotes, three of the four ribosomal RNAs (rRNAs), the 5.8S, 18S and 25S/28S rRNAs, are processed from a single pre-rRNA transcript and assembled into ribosomes. The fourth rRNA, the 5S rRNA, is transcribed by RNA polymerase III and is assembled into the 5S ribonucleoprotein particle (5S RNP), containing ribosomal proteins Rpl5/uL18 and Rpl11/uL5, prior to its incorporation into pre-ribosomes. In mammals the 5S RNP is also central regulator of the homeostasis of the tumour suppressor p53. The nucleolar localisation of the 5S RNP and its assembly into pre-ribosomes is performed by a specialised complex composed of Rpf2 and Rrs1 in yeast or Bxdc1 and hRrs1 in humans. Here we report the structural and functional characterisation of the Rpf2-Rrs1 complex alone, in complex with the 5S RNA and within pre-60S ribosomes. We show that the Rpf2-Rrs1 complex contains a specialised 5S RNA E loop binding module, contacts the Rpl5 protein and also contacts the ribosome assembly factor Rsa4 and the 25S RNA. We propose that the Rpf2-Rrs1 complex establishes a network of interactions that guide the incorporation of the 5S RNP in pre-ribosomes in the initial conformation prior to its rotation to form the central protuberance found in the mature large ribosomal subunit.
2015-07-20 | GSE68431 | GEO
Project description:During transcription the nascent RNA can invade the DNA template, forming extended RNA-DNA duplexes (R-loops). Here we employ ChIP-seq in strains expressing or lacking RNase H to map targets of RNase H activity throughout budding yeast genome. In wild-type strains, R-loops were readily detected over the 35S rDNA region transcribed by Pol I and over the 5S rDNA transcribed by Pol III. In strains lacking RNase H activity, R-loops were elevated over other Pol III genes notably tRNAs, SCR1 and U6 snRNA, and were also associated with the cDNAs of endogenous TY1 retrotransposons, which showed increased rates of mobility to the 5?-flanking regions of tRNA genes. Unexpectedly, R-loops were also associated with mitochondrial genes in the absence of RNase H1, but not of RNase H2. Finally, R-loops were detected on highly expressed protein-coding genes in the wild-type, notably over the second exon of spliced ribosomal protein genes.
2014-11-03 | GSE53420 | GEO
Project description:4C procedure was used for analysis of genomic contacts of rDNA units in HEK 293T cells. The primers for 4C were selected inside IGS. Our data indicate that mostly rDNA units exhibit close proximity with pericentromeric regions in different chromosomes. We also detected the contacts within a rDNA unit and between rDNA units. Examination of rDNA genome-wide contacts in HEK 293T cells using 4C approach.
2014-10-04 | E-GEOD-49193 | biostudies-arrayexpress
Project description:Primate Ribosomal DNA (rDNA) containing BAC clones sequencing
| PRJNA309608 | ENA
Project description:Transcription of the several hundred of mouse and human Ribosomal RNA (rRNA) genes accounts for the majority of RNA synthesis in the cell nucleus and is the determinant of cytoplasmic ribosome abundance, a key factor in regulating gene expression. The rRNA genes, referred to globally as the rDNA, are clustered as direct repeats at the Nucleolar Organiser Regions, NORs, of several chromosomes, and in many cells the active repeats are transcribed at near saturation levels. The rDNA is also a hotspot of recombination and chromosome breakage, and hence understanding its control has broad importance. Despite the need for a high level of rDNA transcription, typically only a fraction of the rDNA is transcriptionally active, and some NORs are permanently silenced by CpG methylation. Various chromatin-remodelling complexes have been implicated in counteracting silencing to maintain rDNA activity. However, the chromatin structure of the active rDNA fraction is still far from clear. Here we have combined a high-resolution ChIP-Seq protocol with conditional inactivation of key basal factors to better understand what determines active rDNA chromatin. The data resolve questions concerning the interdependence of the basal transcription factors, show that preinitiation complex formation is driven by the architectural factor UBF (UBTF) independently of transcription, and exclude a significant role for termination by a torpedomechanism. They further reveal the existence of an asymmetric Boundary Complex formed by CTCF, Cohesin and three phased nucleosomes lying adjacent to the rDNA Enhancer and an arrested RNA Polymerase I complex. We find that this complex is the only site of active histone modification in the whole 45kbp rDNA repeat. Strikingly, the Enhancer Boundary Complex not only delimits each functional rRNA gene, but also is stably maintained after gene inactivation and the re-establishment of surrounding repressive chromatin. Our data define the poised state of rDNA chromatin and place the Enhancer Boundary Complex as the likely entry point for the chromatin remodelling complexes.
2017-07-08 | E-MTAB-5839 | biostudies-arrayexpress
Project description:Sir2 is a highly conserved NAD+-dependent histone deacetylase that functions in heterochromatin formation and promotes replicative lifespan (RLS) in the budding yeast, Saccharomyces cerevisiae. Within the yeast rDNA locus, Sir2 is required for efficient cohesin recruitment and maintaining stability of the tandem array. In addition to the previously reported depletion of Sir2 in replicatively aged cells, we discovered that subunits of the Sir2 containing complexes, SIR and RENT, were depleted. Several other rDNA structural protein complexes also exhibited age-related depletion, most notably the cohesin complex. We hypothesized that mitotic chromosome instability (CIN) due to cohesin depletion could be a driver of replicative aging. ChIP assays of the residual cohesin (Mcd1-13xMyc) in moderately aged cells showed strong depletion from the rDNA and initial redistribution to the point centromeres, which was then lost in older cells. Despite the shift in cohesin distribution, sister chromatid cohesion was partially attenuated in aged cells and the frequency of chromosome loss was increased. This age-induced CIN was exacerbated in strains lacking Sir2 and its paralog, Hst1, but suppressed in strains that stabilize the rDNA array due to deletion of FOB1 or through caloric restriction (CR). Furthermore, ectopic expression of MCD1 from a doxycycline-inducible promoter was sufficient to suppress rDNA instability in aged cells and to extend RLS. Taken together we conclude that age-induced depletion of cohesin and multiple other nucleolar chromatin factors destabilize the rDNA locus, which then results in general CIN and aneuploidy that shortens RLS.
2019-03-12 | GSE117037 | GEO
Project description:Ribosome is the most abundant RNA-protein complex in a cell and many copies of the ribosomal RNA gene (rDNA) have to be maintained. However, arrays of tandemly repeated rDNA genes can lose the copies by intra-repeat recombination. Loss of the rDNA copies of Saccharomyces cerevisiae is counteracted by gene amplification whereby the number of rDNA repeats stabilizes around 150 copies, suggesting the presence of a monitoring mechanism that counts and adjusts the number. Here, we report that in response to rDNA copy loss, the upstream activating factor (UAF) for RNA polymerase I which transcribes the rDNA is released and directly bind to a RNA polymerase II transcribed gene, SIR2 to repress, whose gene products silence rDNA recombination. We show that the amount of UAF determines rDNA copies number that is stably maintained. UAF ensures rDNA production not only by rDNA transcription activation but also by its copy number maintenance.
2019-01-03 | GSE116661 | GEO