End structure of DNA in plasma: detection, characterizationand diagnostic applications
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ABSTRACT:
PROVIDER: EGAS00001004080 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:We aimed at obtaining a reference transcriptome for the European seabass. We characterized by Illumina paired-ends RNA-seq the D. labrax transcriptome for two targeted organs, using a diversity of conditions, animal stages and genotypes to warranty the widest variety of reconstructed transcripts. The brain (including pineal gland and pituitary) and liver were chosen as they are complementary and at a crossroads of many key neuroendocrine, metabolic and behavioral regulations. Dicentrarchus labrax_2 targeted organs (liver and brain) with two technical replicates each (using two different fragment sizes) half a GAIIX run total. We used two flow cells per organ and each was corresponding to a different fragment size. The expected sizes were 350 and 500bp.
2014-02-01 | E-MTAB-1867 | biostudies-arrayexpress
Project description:Most DNA double-strand breaks (DSBs) are harmful to genome integrity. However, some forms of DSBs are essential to biological processes, such as meiotic recombination and V(D)J recombination. DSBs are also required for programmed DNA elimination (PDE) in ciliates and nematodes. In nematodes, the DSBs are healed with telomere addition. While telomere addition sites have been well-characterized, little is known regarding the DSBs that fragment nematode chromosomes. Here, we used embryos from the nematode Ascaris to study the timing of PDE breaks and examine the DSBs and their end processing. Using END-seq, we characterize the DSB ends and demonstrate that DNA breaks are introduced before mitosis, followed by extensive end resection. The resection profile is unique for each break site, and the resection generates 3’ overhangs before the addition of telomeres. Interestingly, telomere healing occurs much more frequently on retained DSB ends than on eliminated ends. This biased repair of the DSB in Ascaris is likely due to the sequestration of the eliminated DNA into micronuclei, preventing their ends from telomere healing. Additional DNA breaks occur within the eliminated DNA in both Ascaris and Parascaris, ensuring chromosomal breakage and providing a fail-safe mechanism for nematode PDE.
2024-03-15 | GSE260958 | GEO
Project description:The structure of broken DNA ends is a critical determinant of the pathway used for DNA double strand break (DSB) repair. Here, we develop an approach, hairpin capture of DNA end structures (HCoDES), which elucidates chromosomal DNA end structures at single nucleotide resolution. HCoDES defines structures of physiologic DSBs generated by the RAG endonuclease, as well as those generated by nucleases widely used for genome editing. Analysis of G1-phase cells deficient in H2AX or 53BP1 reveals DNA ends that are frequently resected to form long single-stranded overhangs that can be repaired by mutagenic pathways. In addition to 3’ overhangs, many of these DNA ends unexpectedly form long 5’ single-stranded overhangs. The divergence in DNA end structures resolved by HCoDES suggests that H2AX and 53BP1 may have distinct activities in end protection. Thus, the high-resolution end structures obtained by HCoDES identify new features of DNA end processing during DSB repair. Single stranded DNA ligation of genomic DNA isolated from G1 arrested LigaseIV-/-, LigaseIV-/- 53BP1-/- and LigaseIV-/- H2AX-/- Abelson pre-B cells harboring site specific DSBs generated by the RAG recombinase, Cas9 endonuclease or Zinc Finger Endonuclease.
2014-12-03 | E-GEOD-62534 | biostudies-arrayexpress
Project description:The structure of broken DNA ends is a critical determinant of the pathway used for DNA double strand break (DSB) repair. Here, we develop an approach, hairpin capture of DNA end structures (HCoDES), which elucidates chromosomal DNA end structures at single nucleotide resolution. HCoDES defines structures of physiologic DSBs generated by the RAG endonuclease, as well as those generated by nucleases widely used for genome editing. Analysis of G1-phase cells deficient in H2AX or 53BP1 reveals DNA ends that are frequently resected to form long single-stranded overhangs that can be repaired by mutagenic pathways. In addition to 3’ overhangs, many of these DNA ends unexpectedly form long 5’ single-stranded overhangs. The divergence in DNA end structures resolved by HCoDES suggests that H2AX and 53BP1 may have distinct activities in end protection. Thus, the high-resolution end structures obtained by HCoDES identify new features of DNA end processing during DSB repair.
2014-12-03 | GSE62534 | GEO
Project description:Deep sequencing of transcriptomes allows quantitative and qualitative analysis of many RNA species in a sample, with parallel comparison of expression levels, splicing variants, natural antisense transcripts, RNA editing and transcriptional start and stop sites the ideal goal. By computational modeling, we show how libraries of multiple insert sizes combined with strand-specific, paired-end (SS-PE) sequencing can increase the information gained on alternative splicing, especially in higher eukaryotes. Despite the benefits of gaining SS-PE data with paired ends of varying distance, the standard Illumina protocol allows only non-strand-specific, paired-end sequencing with a single insert size. Here, we modify the Illumina RNA ligation protocol to allow SS-PE sequencing by using a custom pre-adenylated 3M-bM-^@M-^Y adaptor. We generate parallel libraries with differing insert sizes to aid deconvolution of alternative splicing events and to characterize the extent and distribution of natural antisense transcription in C. elegans. Despite stringent requirements for detection of alternative splicing, our data increases the number of intron retention and exon skipping events annotated in the Wormbase genome annotations by 127 % and 121 %, respectively. We show that parallel libraries with a range of insert sizes increase transcriptomic information gained by sequencing and that by current established benchmarks our protocol gives competitive results with respect to library quality. Sequencing of mRNA from C. elegans with libraries of four differing insert sizes
2012-08-31 | E-GEOD-40507 | biostudies-arrayexpress
Project description:Deep sequencing of transcriptomes allows quantitative and qualitative analysis of many RNA species in a sample, with parallel comparison of expression levels, splicing variants, natural antisense transcripts, RNA editing and transcriptional start and stop sites the ideal goal. By computational modeling, we show how libraries of multiple insert sizes combined with strand-specific, paired-end (SS-PE) sequencing can increase the information gained on alternative splicing, especially in higher eukaryotes. Despite the benefits of gaining SS-PE data with paired ends of varying distance, the standard Illumina protocol allows only non-strand-specific, paired-end sequencing with a single insert size. Here, we modify the Illumina RNA ligation protocol to allow SS-PE sequencing by using a custom pre-adenylated 3’ adaptor. We generate parallel libraries with differing insert sizes to aid deconvolution of alternative splicing events and to characterize the extent and distribution of natural antisense transcription in C. elegans. Despite stringent requirements for detection of alternative splicing, our data increases the number of intron retention and exon skipping events annotated in the Wormbase genome annotations by 127 % and 121 %, respectively. We show that parallel libraries with a range of insert sizes increase transcriptomic information gained by sequencing and that by current established benchmarks our protocol gives competitive results with respect to library quality.
2012-08-31 | GSE40507 | GEO
Project description:Interventions: Group 1: The project aims to:
Statistically compare the fragment length of cell-free DNA in the blood plasma of 80 patients with a confirmed diagnosis of colorectal carcinoma in stages I-IV with the cfDNA fragment lengths of 50 healthy subjects.
For this purpose, residual amounts of blood plasma samples are used, which are collected anyway as part of theroutine examinations.
Cell-free DNA was isolated from the blood plasma and the fragment lengths are measured using qPCR.
The project ends with the publication of the data.
Group 2: Statistically compare the fragment length of cell-free DNA in the blood plasma of 50 healthy subjects with 80 patients with a confirmed diagnosis of colorectal carcinoma in stages I-IV.
The plasma samples from healthy volunteers were purchased (Central Biohub GmbH).
Primary outcome(s): The aim of this study is: 1) to analyze total cfDNA concentration in CRC patients with different histopathological stages (UICC I-IV). 2) to address the question whether the integrity index of cfDNA increases in CRC patients as a result of elevated necrotic degradation processes. Therefore, we intended to quantify short and long fragments of cfDNA via qPCR independent from total cfDNA levels by using equal template concentrations for CRC patients and healthy individuals. This approach may help to understand whether previously described diagnostic markers are either increased, decreased or unaltered in blood plasma of CRC patients compared to healthy individuals.
Study Design: Allocation: ; Masking: ; Control: ; Assignment: ; Study design purpose: basic science
| 2754663 | ecrin-mdr-crc
Project description:Transcription termination is mechanistically coupled to pre-mRNA 3â end formation to prevent transcription much beyond the gene 3â end. C. elegans, however, engages in polycistronic transcription of operons in which 3â end formation between genes is not accompanied by termination. We have performed RNA polymerase II (RNAPII) and CstF ChIP-seq experiments to investigate at a genome-wide level how RNAPII can transcribe through multiple poly-A signals without causing termination. Our data shows that transcription proceeds in some ways as if operons were composed of multiple adjacent single genes. Total RNAPII shows a small peak at the promoter of the gene cluster and a much larger peak at 3â ends. These 3â peaks coincide with maximal phosphorylation of Ser2 within the C-terminal domain (CTD) of RNAPII and maximal localization of the 3â end formation factor CstF. This pattern occurs at all 3â ends including those at internal sites in operons where termination does not occur. Thus the normal mechanism of 3â end formation does not always result in transcription termination. Furthermore, reduction of CstF50 by RNAi did not substantially alter the pattern of CstF64, total RNAPII, or Ser2 phosphorylation at either internal or terminal 3â ends. However, CstF50 RNAi did result in a subtle reduction of CstF64 binding upstream of the site of 3â cleavage, suggesting that the CstF50/CTD interaction may facilitate bringing the 3â end machinery to the transcription complex. RNA-seq analysis of wild type (empty vector) and RNAi CstF50 mRNA (polyA-selected) and rRNA-depleted RNA (total RNA).
2016-04-02 | E-GEOD-79822 | biostudies-arrayexpress
Project description:Transcription termination is mechanistically coupled to pre-mRNA 3â end formation to prevent transcription much beyond the gene 3â end. C. elegans, however, engages in polycistronic transcription of operons in which 3â end formation between genes is not accompanied by termination. We have performed RNA polymerase II (RNAPII) and CstF ChIP-seq experiments to investigate at a genome-wide level how RNAPII can transcribe through multiple poly-A signals without causing termination. Our data shows that transcription proceeds in some ways as if operons were composed of multiple adjacent single genes. Total RNAPII shows a small peak at the promoter of the gene cluster and a much larger peak at 3â ends. These 3â peaks coincide with maximal phosphorylation of Ser2 within the C-terminal domain (CTD) of RNAPII and maximal localization of the 3â end formation factor CstF. This pattern occurs at all 3â ends including those at internal sites in operons where termination does not occur. Thus the normal mechanism of 3â end formation does not always result in transcription termination. Furthermore, reduction of CstF50 by RNAi did not substantially alter the pattern of CstF64, total RNAPII, or Ser2 phosphorylation at either internal or terminal 3â ends. However, CstF50 RNAi did result in a subtle reduction of CstF64 binding upstream of the site of 3â cleavage, suggesting that the CstF50/CTD interaction may facilitate bringing the 3â end machinery to the transcription complex. ChIP-seq examination of RNAPII and CstF subunits using C. elegans in duplicates.
2016-04-02 | E-GEOD-79821 | biostudies-arrayexpress