BAMscale: quantification of DNA sequencing peaks and generation of scaled coverage tracks
Ontology highlight
ABSTRACT: We present a tool for processing NGS DNA-seq BAM files to quantify peaks and create coverage tracks from ChIP-seq, NS-seq, ATAC-seq, OK-seq, END-seq and replication timing data
Project description:BackgroundNext-generation sequencing allows genome-wide analysis of changes in chromatin states and gene expression. Data analysis of these increasingly used methods either requires multiple analysis steps, or extensive computational time. We sought to develop a tool for rapid quantification of sequencing peaks from diverse experimental sources and an efficient method to produce coverage tracks for accurate visualization that can be intuitively displayed and interpreted by experimentalists with minimal bioinformatics background. We demonstrate its strength and usability by integrating data from several types of sequencing approaches.ResultsWe have developed BAMscale, a one-step tool that processes a wide set of sequencing datasets. To demonstrate the usefulness of BAMscale, we analyzed multiple sequencing datasets from chromatin immunoprecipitation sequencing data (ChIP-seq), chromatin state change data (assay for transposase-accessible chromatin using sequencing: ATAC-seq, DNA double-strand break mapping sequencing: END-seq), DNA replication data (Okazaki fragments sequencing: OK-seq, nascent-strand sequencing: NS-seq, single-cell replication timing sequencing: scRepli-seq) and RNA-seq data. The outputs consist of raw and normalized peak scores (multiple normalizations) in text format and scaled bigWig coverage tracks that are directly accessible to data visualization programs. BAMScale also includes a visualization module facilitating direct, on-demand quantitative peak comparisons that can be used by experimentalists. Our tool can effectively analyze large sequencing datasets (~?100 Gb size) in minutes, outperforming currently available tools.ConclusionsBAMscale accurately quantifies and normalizes identified peaks directly from BAM files, and creates coverage tracks for visualization in genome browsers. BAMScale can be implemented for a wide set of methods for calculating coverage tracks, including ChIP-seq and ATAC-seq, as well as methods that currently require specialized, separate tools for analyses, such as splice-aware RNA-seq, END-seq and OK-seq for which no dedicated software is available. BAMscale is freely available on github (https://github.com/ncbi/BAMscale).
Project description:BackgroundAlthough QRS duration (QRSd) is an important determinant of cardiac resynchronization therapy (CRT) response, non-responder rates remain high. QRS fragmentation can also reflect electrical dyssynchrony. We hypothesized that quantification of abnormal QRS peaks (QRSp) would predict CRT response.MethodsForty-seven CRT patients (left ventricular ejection fraction = 23±7%) were prospectively studied. Digital 12-lead ECGs were recorded during native rhythm at baseline and 6 months post-CRT. For each precordial lead, QRSp was defined as the total number of peaks detected on the unfiltered QRS minus those detected on a smoothed moving average template QRS. CRT response was defined as >5% increase in left ventricular ejection fraction post-CRT.ResultsSixty-percent of patients responded to CRT. Baseline QRSd was similar in CRT responders and non-responders, and did not change post-CRT regardless of response. Baseline QRSp was greater in responders than non-responders (9.1±3.5 vs. 5.9±2.2, p = 0.001) and decreased in responders (9.2±3.6 vs. 7.9±2.8, p = 0.03) but increased in non-responders (5.5±2.3 vs. 7.5±2.8, p = 0.049) post-CRT. In multivariable analysis, QRSp was the only independent predictor of CRT response (Odds Ratio [95% Confidence Interval]: 1.5 [1.1-2.1], p = 0.01). ROC analysis revealed QRSp (area under curve = 0.80) to better discriminate response than QRSd (area under curve = 0.67). Compared to QRSd ≥150ms, QRSp ≥7 identified response with similar sensitivity but greater specificity (74 vs. 32%, p<0.05). Amongst patients with QRSd <150ms, more patients with QRSp ≥7 responded than those with QRSp <7 (75 vs. 0%, p<0.05).ConclusionsOur novel automated QRSp metric independently predicts CRT response and decreases in responders. Electrical dyssynchrony assessed by QRSp may improve CRT selection and track structural remodeling, especially in those with QRSd <150ms.
Project description:Fibroblasts rely on adhesive structures to migrate. It is generally thought that adhesive structures disassemble once at the rear of the cell to release the cell and allow further movement. However, a significant portion of adhesions is not disassembled and is instead left on the substrate. We observed that virtually all the non-resorbed adhesions remain connected to the substrate by the means of integrin β5. Forward cell migration results in plasma membrane pulling giving rise to tubular structures that are then left on the ground, forming a network of lipid tracks that persist for several days, thus altering substrate’s topography. Cancer cells of different origin exploit fibroblast-tracks as migration railways. The adhesion of cancer cells along tracks is not mediated by focal adhesions, but rather by frustrated clathrin-coated structures (CCSs). Analysis of the composition of track generated by cancer associated fibroblasts allowed to identify integrin αv as the receptor on cancer cells responsible for track recognition. Some cancer cell lines are not able to perform durotaxis (rigidity driven migration), while fibroblasts are very good at it. We thus tested whether, in the presence of fibroblast-tracks, non-durotactic cancer cells would become durotactic by following tracks and this was indeed the case. Hence, fibroblast-tracks are a novel structure capable of physically directing cell migration of different cell types.
Project description:Glioblastoma (GBM) is highly invasive primary brain tumor. Here, we retraced early steps of GBM invasion and interactions with tumor-associated myeloid cells (TAM) in a highly infiltrative murine GBM model in immunocompetent background. We reveal early mobilization of microglia in a wide onco-field ahead of GBM invasion, forming glial nets encircling tumor micro-infiltrates that are enmeshed with a dense network of extracellular matrix (ECM). Physical contacts with GBM cells initiate an astounding morphological, spatial, and functional transformation of microglia and monocyte-derived macrophages to form collectively organized migration streams with intertwined GBM cells, paralleled by major ECM restructuring along invasion tracks. Mechanistically, this requires upregulation of guidance receptor Plexin-B2 in TAM, which functions to resolve collisions with GBM cells by providing cell contact guidance for cell alignment and ECM restructuring. Together, our results on stage- and niche-specific mobilization of microglia/macrophages, on governing factors, and the molecular insights into pro-invasion signaling open new therapeutic opportunities to curb GBM invasion.
Project description:Glioblastoma (GBM) is highly invasive primary brain tumor. Here, we retraced early steps of GBM invasion and interactions with tumor-associated myeloid cells (TAM) in a highly infiltrative murine GBM model in immunocompetent background. We reveal early mobilization of microglia in a wide onco-field ahead of GBM invasion, forming glial nets encircling tumor micro-infiltrates that are enmeshed with a dense network of extracellular matrix (ECM). Physical contacts with GBM cells initiate an astounding morphological, spatial, and functional transformation of microglia and monocyte-derived macrophages to form collectively organized migration streams with intertwined GBM cells, paralleled by major ECM restructuring along invasion tracks. Mechanistically, this requires upregulation of guidance receptor Plexin-B2 in TAM, which functions to resolve collisions with GBM cells by providing cell contact guidance for cell alignment and ECM restructuring. Together, our results on stage- and niche-specific mobilization of microglia/macrophages, on governing factors, and the molecular insights into pro-invasion signaling open new therapeutic opportunities to curb GBM invasion.
Project description:MotivationA common way to summarize sequencing datasets is to quantify data lying within genes or other genomic intervals. This can be slow and can require different tools for different input file types.ResultsMegadepth is a fast tool for quantifying alignments and coverage for BigWig and BAM/CRAM input files, using substantially less memory than the next-fastest competitor. Megadepth can summarize coverage within all disjoint intervals of the Gencode V35 gene annotation for more than 19,000 GTExV8 BigWig files in approximately one hour using 32 threads. Megadepth is available both as a command-line tool and as an R/Bioconductor package providing much faster quantification compared to the rtracklayer package.Availabilityhttps://github.com/ChristopherWilks/megadepth,https://bioconductor.org/packages/megadepth.
Project description:Expansion of triplex-forming GAA/TTC repeats in the first intron of FRDA gene is known to cause Friedreich’s ataxia. Besides FRDA, there are a number of other highly polymorphic GAA/TTC loci in the human genome where the size variations so far were considered to be a neutral event. Using yeast as a model system, we demonstrate that expanded GAA/TTC repeats represent a threat to eukaryotic genome integrity by triggering double-strand breaks and gross chromosomal rearrangements. The fragility potential strongly depends on the length of the track and orientation of the repeats relative to the replication origin which correlates with their propensity to adopt secondary structure and to block replication progression. We show that fragility is mediated by mismatch repair machinery and requires the MutS(beta) and endonuclease activity of MutL(alpha). We suggest that the mechanism of GAA/TTC-induced chromosome aberrations defined in yeast can also operate in human carriers with expanded tracks. Keywords: CGH-array