Pacasus: Long reads and whole-genome amplication
Ontology highlight
ABSTRACT:
PROVIDER: PRJEB21791 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| Other | ||||
| ERR2036091_1.fastq.gz | Fastqsanger.gz | |||
| ERR2036091_2.fastq.gz | Fastqsanger.gz | |||
| ERR2036092_1.fastq.gz | Fastqsanger.gz | |||
| ERR2036092_2.fastq.gz | Fastqsanger.gz |
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Project description:The IgH 3â?? regulatory region (3â??RR) controls class switch recombination (CSR) and somatic hypermutation (SHM) in B cells. The mouse 3â??RR contains four enhancer elements with hs1,2 flanked by inverted repeated sequences and the center of a 25-kb palindrome bounded by two hs3 enhancer inverted copies (hs3a and hs3b). hs4 lies downstream of the palindrome. Evolution maintained in mammals this unique palindromic arrangement suggesting that it is functionally significant. We report that deconstructing the palindromic IgH 3â??RR strongly impacts its function even when enhancers are preserved. CSR and IgH transcription appear poorly dependent from the 3â??RR architecture and are more or less preserved provided 3â??RR enhancers are present. By contrast, an â??architectural effectâ?? significantly lowers VH germline transcription, AID recruitment and SHM. In conclusion, this work indicates that the IgH 3â??RR does not simply pile up enhancer units but also optimally expose them into a functional architecture of crucial importance. RNAseq analysis of B-cell splenocytes with (S=stimulated) or without (R=resting) LPS activation from wt, delta2leftPAL, and deltaIRIS mice.
2016-02-08 | E-GEOD-76359 | biostudies-arrayexpress
Project description:The IgH 3’ regulatory region (3’RR) controls class switch recombination (CSR) and somatic hypermutation (SHM) in B cells. The mouse 3’RR contains four enhancer elements with hs1,2 flanked by inverted repeated sequences and the center of a 25-kb palindrome bounded by two hs3 enhancer inverted copies (hs3a and hs3b). hs4 lies downstream of the palindrome. Evolution maintained in mammals this unique palindromic arrangement suggesting that it is functionally significant. We report that deconstructing the palindromic IgH 3’RR strongly impacts its function even when enhancers are preserved. CSR and IgH transcription appear poorly dependent from the 3’RR architecture and are more or less preserved provided 3’RR enhancers are present. By contrast, an “architectural effect” significantly lowers VH germline transcription, AID recruitment and SHM. In conclusion, this work indicates that the IgH 3’RR does not simply pile up enhancer units but also optimally expose them into a functional architecture of crucial importance.
2016-02-08 | GSE76359 | GEO
Project description:ParA and ParB homologs are involved in accurate chromosome segregation in bacteria. ParBs participate in proper folding and initial separation of ori domains by binding to specific parS sites (palindromic centromere-like sequences), mainly localized close to oriC. Bioinformatic analyses identified 10 parS sequences in the Pseudomonas aeruginosa PAO1 genome. One parS from the parS1-parS4 cluster is required for ParB mediated chromosome segregation. To verify the binding of ParB to all known parSs in vivo as well as to identify additional ParB binding sites we performed chromation immunoprecipitation (ChIP) using polyclonal anti-ParB antibodies followed by high throughput sequencing. ChIP was performed with P. aeruginosa PAO1161 (WT) cells, PAO1161 pKB9 (ParB+++) cells with a slight, non-toxic ParB overproduction as well as with 3 strains containing parS modifications impairing ParB binding to these sites. The data confirmed ParB binding to all known parS sequences with the exception of parS5. Moreover, we identified more than a 1000 of new ParB-bound regions, majority of which contained a DNA motif corresponding to inner 7 nt from one arm of the parS palindrome. ParB interactions with these numerous sites could affect chromosome topology, compaction and gene expression classifying P. aeruginosa ParB as a Nucleoid Associated Protein (NAP).
2018-03-27 | GSE110158 | GEO
Project description:Numerous B-cell lymphomas feature translocations linking oncogenes with the IgH locus and epigenetic drugs such as histone deacetylase inhibitors (HDACi) have been approved to treat some of them. In this study we investigated IgH locus transcription in B-cell splenocytes stimulated with LPS and the HDACi SAHA. B-cell development is spatially and temporally regulated with the 3'RR enhancer of the IgH locus as a conductor. 3'RR is composed of 4 enhancer elements with a palindromic structure of great significance. We investigated the role of this palindrome with KOKI mice where the 30Kb structure of the 3'RR has been deleted of its palindromic structure.
2021-03-27 | GSE169690 | GEO
Project description:<p>DNA Inverted Repeats as an At-risk Motif for Palindromic Gene Amplificatio defines oncogene amplification that is configured as a series of inverted duplications (palindromic gene amplification). There are several, recurrently amplified oncogenes throughout the human genome. However, it remains unclear whether this recurrent amplification is solely a manifestation of increased fitness resulting from random amplification mechanisms, or if genomic locus-specific amplification mechanism plays a role. </p> <p>In this study, we show that the ERBB2 oncogene at 17q12 is susceptible to palindromic gene amplification in HER2-positive breast tumors. We investigated eight tumors in this study, of which five tumors were HER2-positive, and three tumors were HER2-negative. HER2-status was determined by clinical FISH tests. We applied three genomic approaches to investigate the amplification mechanism: (1) copy number analysis by array-CGH on the Affymetrix SNP6.0 platform (8 files), (2) sequencing of DNA libraries enriched with tumor-derived palindromic DNA (Genome-wide Analysis of Palindrome Formation, GAPF-seq) (8 files) and (3) unbiased whole genome sequencing (WGS) (1 file). These molecular data is made available in the dbGaP. </p> <p>Genomic studies using tumor DNA was approved under the Internal Institutional Review Board at the Cleveland Clinic (IRB07-136: EXEMPT: Chromosome Breakage and DNA Palindrome Formation). Specimens were obtained and methods were carried out under the auspices of IRB 7881 (Evaluation of Genetic and Molecular Markers in Patients with Breast Cancer). All patients consented to allow their cancer specimens to be used by researchers in an anonymized fashion. The consent form indicates that publication will take place without identifiers to protect the identity of any specific individual.</p> <p>We observed significant and enrichment of palindromic DNA within amplified ERBB2 genomic segments in four out of five HER2-positive tumors. None of three HER2-negative tumors showed such enrichment. Palindromic DNA was particularly enriched at amplification peaks and boundaries between amplified and normal copy-number regions. Thus, palindromic gene amplification shaped the amplified ERBB2 locus. The moderate enrichment of palindromic DNA throughout the amplified segments leads us to propose that the ERBB2 locus is amplified through a mechanism that repeatedly generates palindromic DNA, such as Breakage-Fusion-Bridge cycles. Our results reveal a potential interaction between local genomic environments and gene amplification mechanisms. </p> <p>This study is published under the title "Palindromic amplification of the ERBB2 oncogene in primary HER2-positive breast tumors" <a href="https://www.ncbi.nlm.nih.gov/pubmed/?term=28211519" target="_blank">(PMID:28211519)</a>. </p>
| phs001261 | dbGaP
Project description:P6 palindrome
| PRJEB44535 | ENA
Project description:Background: Insufficient quantities of human genomic DNA are a limiting factor for many clinical applications. Whole genome amplification (WGA) is an approach designed to overcome small amount of DNA for genome-wide genetic tests as it allows amplification of the entire genome from picogram or nanogram quantities of DNA. Various strategies of WGA have been developed; however, none of them can guarantee the absence of amplification bias. High-quality genome-representative amplified DNA is crucial for WGA use in basic research and clinical genetics. Thus, systematic evaluation of WGA effect on downstream methods is necessary. Results: In this paper, 4 multiple displacement amplification (MDA) -based and 2 PCR-based WGA kits were compared in their effect on segmental copy-number changes as well as copy-number neutral loss of heterozygosity detection by high-density oligonucleotide DNA arrays. We described outcomes and limits for each individual WGA; however, the main goal of this study was chiefly to show a general compatibility and features specific for particular WGA strategy. The main outcomes are as follows: 1) MDA-based WGAs showed higher tendency to generate false positive imbalances in contrast to PCR-based WGAs with higher risk of false negativity; 2) the specific risk of false positivity and/or negativity increased with decreasing copy-number segments size; 3) single-cell WGAs showed significantly worse effect on results in comparison to WGAs with nanogram level of DNA as input; 4) PCR-based WGAs were not compatible with copy-number neutral loss of heterozygosity analysis based on single nucleotide polymorphisms in restriction digestion sites and also showed higher risk of copy-number neutral loss of heterozygosity false negativity if combined with analysis based on simple hybridization. Conclusions: This study gives a comprehensive insight into the WGA effect on DNA array analysis. The results of this study help to choose WGA according to individual user requirements and options. Moreover, we show a strategy to verify and validate segmental copy-number changes detection by DNA array protocol including any WGA for any purpose to attain the highest efficiency without an unnecessary WGA bias.
2015-09-29 | GSE73513 | GEO
Project description:Dehalococcoides mccartyi are functionally important bacteria that catalyze the reductive dechlorination of chlorinated ethenes. However, these anaerobic bacteria are fastidious to isolate, making downstream genomic characterization challenging. In order to facilitate genomic analysis, a fluorescence-activated cell sorting (FACS) method was developed in this study to separate D. mccartyi cells from a microbial community, and the DNA of the isolated cells was processed by whole genome amplification (WGA) and hybridized onto a D. mccartyi microarray for comparative genomics against four sequenced strains. First, FACS was successfully applied to a D. mccartyi isolate as positive control, and then microarray results verified that WGA from 10(6) cells or ~1 ng of genomic DNA yielded high-quality coverage detecting nearly all genes across the genome. As expected, some inter- and intrasample variability in WGA was observed, but these biases were minimized by performing multiple parallel amplifications. Subsequent application of the FACS and WGA protocols to two enrichment cultures containing ~10% and ~1% D. mccartyi cells successfully enabled genomic analysis. As proof of concept, this study demonstrates that coupling FACS with WGA and microarrays is a promising tool to expedite genomic characterization of target strains in environmental communities where the relative concentrations are low.
2015-01-31 | GSE54040 | GEO
Project description:We developed a strategy to map GlcNAc modified proteins based on a chemical chromatin precipitation strategy. Drosophila S2 cells, as well as wild type (wt) and sxc null pupae, were fed with 100 uM Ac4GalNAz and the resulting DNA was cross-linked, sonicated, and purified. DNA strands cross-linked to GlcNAz proteins were isolated by congugating with alkyn-biotin by Staudinger ligation followed by streptavidin purification. The resulting DNA was constructed into libraries for sequencing. To asses the robustness of our strategy, we compared GalNAz ChIP-seq results in S2 cells with two other GlcNAc ChIP-seq strategies, using a mutant β-1,4-galactosyltransferase (GalT) and the lecting wheat germ agglutinin (WGA). Briefly, GalT was incubated with cross-linked, sonicated and purified DNA along with UDP-GalNAz. Ligation to biotin with click chemistry followed by streptavidin purification resulted in library ready material. For WGA and Pho ChIP-seq, cross-linked and purified DNA was incubated with pho antibody or WGA resin and purified followed by library preperation.
2017-07-18 | GSE84502 | GEO
Project description:Dehalococcoides mccartyi are functionally important bacteria that catalyze the reductive dechlorination of chlorinated ethenes. However, these anaerobic bacteria are fastidious to isolate, making downstream genomic characterization challenging. In order to facilitate genomic analysis, a fluorescence-activated cell sorting (FACS) method was developed in this study to separate D. mccartyi cells from a microbial community, and the DNA of the isolated cells was processed by whole genome amplification (WGA) and hybridized onto a D. mccartyi microarray for comparative genomics against four sequenced strains. First, FACS was successfully applied to a D. mccartyi isolate as positive control, and then microarray results verified that WGA from 106 cells or M-bM-^HM-<1 ng of genomic DNA yielded high-quality coverage detecting nearly all genes across the genome. As expected, some inter- and intrasample variability in WGA was observed, but these biases were minimized by performing multiple parallel amplifications. Subsequent application of the FACS and WGA protocols to two enrichment cultures containing M-bM-^HM-<10% and M-bM-^HM-<1% D. mccartyi cells successfully enabled genomic analysis. As proof of concept, this study demonstrates that coupling FACS with WGA and microarrays is a promising tool to expedite genomic characterization of target strains in environmental communities where the relative concentrations are low. The genomic DNA (gDNA) of each culture or sorted and amplifed DNA was analyzed in triplicate.
2015-01-31 | E-GEOD-54040 | biostudies-arrayexpress