Leishmania spp
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA312841 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR353508.fastq.gz | Fastqsanger.gz | |||
| SRR353509.fastq.gz | Fastqsanger.gz | |||
| SRR353510.fastq.gz | Fastqsanger.gz | |||
| SRR353511.fastq.gz | Fastqsanger.gz | |||
| SRR353512.fastq.gz | Fastqsanger.gz |
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Project description:5-hydroxymethyluracil (5hmU) is a thymine base modification found in genomes of a diverse range of organisms. To explore the functional importance of 5hmU, we developed a method for the genome-wide mapping of 5hmU-modified loci based on a chemical tagging strategy for the hydroxymethyl group. We applied the method to generate genome-wide maps of 5hmU in parasitic protozoan Leishmania, where 5hmU forms enzymatically via hydroxylation of thymine. In the genus, another thymine modification 5-(β-glucopyranosyl) hydroxymethyluracil (base J) plays key roles during transcription. To elucidate relationships between 5hmU and base J, we also mapped base J loci by introducing a chemical tagging strategy for the glucopyranoside residue. Results: Observed 5hmU peaks were highly consistent among technical replicates, confirming the robustness of the method. 5hmU were particularly enriched in strand switch regions, telomeric regions and intergenic regions. Over 90% of 5hmU-enriched loci overlapped with base J-enriched loci, which occurred mostly within strand switch regions. We also identified loci comprising 5hmU but not base J. These 5hmU-specific loci were enriched with motifs consisting of a stretch of thymine bases and associated with higher RNA levels. Conclusions: By chemically detecting 5hmU we provide the first genome-wide map of 5hmU, which will help addressing the emerging interest in the role of 5hmU. The presence of 5hmU-specific loci may suggest that 5hmU has unique roles.
2016-12-15 | GSE83384 | GEO
Project description:Base J is a modified DNA base that is enriched at RNA polymerase II termination sites. We previously identified a complex in Leishmania major and T. brucei composed of PNUTS, PP1, Wdr82 and a J-binding protein (JBP3). We show that deletion of PP1 in L. major leads to readthrough transcription and expression of downstream genes.
2022-10-01 | GSE200788 | GEO
Project description:Amphotericin B resistance in Leishmania mexicana: Alterations to sterol metabolism, lipid transport and oxidative stress response
| PRJNA763929 | ENA
Project description:Some T's in nuclear DNA of trypanosomes and Leishmania are hydroxylated and glucosylated to yield base J (?-D-glucosyl-hydroxymethyluracil). In Leishmania about 99% of J is located in telomeric repeats. We show here that most of the remaining J is located at chromosome-internal RNA Polymerase II termination sites. Both this internal J and telomeric J can be reduced by a knockout of J-binding protein 2 (JBP2), an enzyme involved in the first step of J biosynthesis. J levels are further reduced by growing Leishmania JBP2 knockout cells in BrdU-containing medium, resulting in cell death. The loss of internal J is accompanied by massive read-through at RNA Polymerase II termination sites. The degree of read-through varies between transcription units, but may extend over 100 kb. We conclude that J is required for proper transcription termination and infer that the absence of internal J kills Leishmania by massive read-through of transcriptional stops. We determined the exact location of base J in the genome of Leishmania by high-throughput sequencing of J containing DNA fragments. Samples were enriched for J-containing fragments by two independent methods: ChIP using an anti-J DNA antibody or by binding to a the J-binding protein JBP1. We studied the effect of loss of J on transcription using WT, JBP2 knockout (30-37% of WT level J), and JBP2 knockout cells grown in BrdU containing medium (13-16% of WT level of J). We used 6 RNA-seq libraries (three samples & two replica each) containing processed RNA products (transspliced and poly-adenylated) and 3 small RNA libraries representing the entire transcriptome.
2011-10-15 | E-GEOD-32976 | biostudies-arrayexpress
Project description:Chromatin-associated protein complexes link DNA base J and transcription termination in Leishmania
| PRJNA657084 | ENA
Project description:Protein-coding genes in kinetoplastid protists are transcribed from polycistronic arrays, yielding RNA precursors which are processed to form mature transcripts bearing a 5’ spliced leader (SL) and 3’ poly(A) tract. Regions of transcription initiation and termination lack known eukaryotic promoter and terminator elements, and current data suggest that transcription is instead regulated predominantly through epigenetic mechanisms. Several epigenetic marks, including histone modifications, histone variants, and an atypical DNA modification known as base J have been localized to regions of transcription initiation or termination in Trypanosoma brucei, Trypanosoma cruzi, and/or Leishmania major. Despite this conservation, the phenotypes of base J mutants vary significantly across trypanosomatids, suggesting that the specific epigenetic networks governing transcription initiation and termination have diverged significantly during evolution. In this light, we sought to characterize and compare the roles of the histone variants H2A.Z, H2B.V, and H3.V in L. major. As in T. brucei, the histone variants H2A.Z and H2B.V were shown to be essential in L. major using a powerful quantitative plasmid segregation-based test. In contrast and again similar to T. brucei, H3.V is not essential in Leishmania as H3.V-null lines grew normally, resembled WT, and remained infectious. Using SL-primed RNA-seq, we found that H3.V-null parasites have steady-state transcript levels comparable to WT parasites and display no defects in the efficiency of transcription termination at convergent strand switch regions (SSRs). Our results show a conservation of histone variant phenotypes between L. major and T. brucei, in contrast to the phenotypes associated with the epigenetic DNA base J modification.
2013-10-26 | GSE51737 | GEO
Project description:The modified DNA base 5-hydroxymethylcytosine (5hmC) is enriched in neurons where it may contribute to gene function and cellular identity. To address this issue in an in vivo neuronal population, we assessed the patterning, stability, and function of the base within gene bodies in olfactory sensory neurons. We find that gene body 5hmC linearly correlates with transcriptional output and is stable in fully mature neurons and those lacking de novo methyltransferase activity. Overexpression of Tet3, which oxidizes methylated cytosines (5mC) to 5hmC, markedly alters gene body 5hmC levels and provides evidence that 5hmC facilitates transcription. This manipulation disrupts olfactory receptor expression and the targeting of axons to the olfactory bulb, key molecular and anatomical features of the olfactory system that are necessary for proper physiology. Our results support a direct, positive and physiologically significant role for gene body 5hmC in transcriptional elongation and the maintenance of cellular identity independent of its function as an intermediate to demethylation. We assessed the role of 5hmC in mature olfactory sensory neurons by assessing 5hmC levels in 2 month old neurons, olfactory epithelia lacking Dnmt3a, and mOSNs overexpressing Tet3. To determine genome-wide levels of 5hmC, we performed DNA immunoprecipitation coupled to Illumina sequencing. To determine transcript levels, we prepared and sequenced rRNA-depleted cDNA libraries.
2013-09-03 | E-GEOD-43617 | biostudies-arrayexpress
Project description:Base J is a modified DNA base that is enriched at RNA polymerase II termination sites. We previously found that base J functions to prevent readthrough transcription within gene clusters via the PJW/PP1 complex. Analysis of the complex in T. brucei faild to identify the catalytic PP1 component. We now show the RNAi ablation of PP1-1 in T. brucei leads to readthrough transcription and expression of downstream genes.
2024-07-17 | GSE244975 | GEO
Project description:A work for studying the effect of rs1192691 on repressing VAV3 enhancer activity via affecting EZH2 enrichment at the SNP location.
2022-01-18 | GSE186025 | GEO
Project description:Protein-coding genes in kinetoplastid protists are transcribed from polycistronic arrays, yielding RNA precursors which are processed to form mature transcripts bearing a 5M-bM-^@M-^Y spliced leader (SL) and 3M-bM-^@M-^Y poly(A) tract. Regions of transcription initiation and termination lack known eukaryotic promoter and terminator elements, and current data suggest that transcription is instead regulated predominantly through epigenetic mechanisms. Several epigenetic marks, including histone modifications, histone variants, and an atypical DNA modification known as base J have been localized to regions of transcription initiation or termination in Trypanosoma brucei, Trypanosoma cruzi, and/or Leishmania major. Despite this conservation, the phenotypes of base J mutants vary significantly across trypanosomatids, suggesting that the specific epigenetic networks governing transcription initiation and termination have diverged significantly during evolution. In this light, we sought to characterize and compare the roles of the histone variants H2A.Z, H2B.V, and H3.V in L. major. As in T. brucei, the histone variants H2A.Z and H2B.V were shown to be essential in L. major using a powerful quantitative plasmid segregation-based test. In contrast and again similar to T. brucei, H3.V is not essential in Leishmania as H3.V-null lines grew normally, resembled WT, and remained infectious. Using SL-primed RNA-seq, we found that H3.V-null parasites have steady-state transcript levels comparable to WT parasites and display no defects in the efficiency of transcription termination at convergent strand switch regions (SSRs). Our results show a conservation of histone variant phenotypes between L. major and T. brucei, in contrast to the phenotypes associated with the epigenetic DNA base J modification. Total RNA from Four LmjF samples were analyzed using RNA-Seq. One of them is wildtype parasites, one is single knockout for H3V gene and two independent double knockouts for H3V gene.
2013-10-26 | E-GEOD-51737 | biostudies-arrayexpress