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ATAC-Seq of Batf-deficient pDC Transcriptomes (CpG 0h, 2h)

ABSTRACT: Purpose: The goals of this study are to compare the pDC chromatin structure (ATAC-seq) at steady state and at 2h after CpG activation. Methods: Cells were harvested and frozen in culture media containing FBS and 5% DMSO. Cryopreserved cells were sent to Active Motif to perform the ATAC-seq assay. The cells were then thawed in a 37°C water bath, pelleted, washed with cold PBS, and tagmented as previously described (Buenrostro et al., 2013), with some modifications based on (Corces et al., 2017). Briefly, cell pellets were resuspended in lysis buffer, pelleted, and tagmented using the enzyme and buffer provided in the Nextera Library Prep Kit (Illumina). Tagmented DNA was then purified using the MinElute PCR purification kit (Qiagen), amplified with 10 cycles of PCR, and purified using Agencourt AMPure SPRI beads (Beckman Coulter). Resulting material was quantified using the KAPA Library Quantification Kit for Illumina platforms (KAPA Biosystems), and sequenced with PE42 sequencing on the NextSeq 500 sequencer (Illumina). Results: Reads were aligned using the BWA algorithm (mem mode; default settings). Duplicate reads were removed, only reads mapping as matched pairs and only uniquely mapped reads (mapping quality >= 1) were used for further analysis. Alignments were extended in silico at their 3’-ends to a length of 200 bp and assigned to 32-nt bins along the genome. The resulting histograms (genomic “signal maps”) were stored in bigWig files. Peaks were identified using the MACS 2.1.0 algorithm at a cut off of p-value 1e-7, without control file, and with the –nomodel option. Peaks that were on the ENCODE blacklist of known false ChIP-Seq peaks were removed. Signal maps and peak locations were used as input data to Active Motifs proprietary analysis program, which creates Excel tables containing detailed information on sample comparison, peak metrics, peak locations and gene annotations. For differential analysis, reads were counted in all merged peak regions (using Subread), and the replicates for each condition were compared using DESeq2. Conclusions: Our study represents a detailed analysis of naive and activated pDC chromatin that analyzes the role of the transcription factor BATF for chromatin structure in pDCs.

ORGANISM(S): Mus musculus

PROVIDER: GSE178410 | GEO | 2024/01/12

REPOSITORIES: GEO

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Project description:Purpose: The goals of this study are to compare the pDC chromatin structure (ATAC-seq) at steady state and at 2h after CpG activation. Methods: Cells were harvested and frozen in culture media containing FBS and 5% DMSO. Cryopreserved cells were sent to Active Motif to perform the ATAC-seq assay. The cells were then thawed in a 37°C water bath, pelleted, washed with cold PBS, and tagmented as previously described (Buenrostro et al., 2013), with some modifications based on (Corces et al., 2017). Briefly, cell pellets were resuspended in lysis buffer, pelleted, and tagmented using the enzyme and buffer provided in the Nextera Library Prep Kit (Illumina). Tagmented DNA was then purified using the MinElute PCR purification kit (Qiagen), amplified with 10 cycles of PCR, and purified using Agencourt AMPure SPRI beads (Beckman Coulter). Resulting material was quantified using the KAPA Library Quantification Kit for Illumina platforms (KAPA Biosystems), and sequenced with PE42 sequencing on the NextSeq 500 sequencer (Illumina). Results: Reads were aligned using the BWA algorithm (mem mode; default settings). Duplicate reads were removed, only reads mapping as matched pairs and only uniquely mapped reads (mapping quality >= 1) were used for further analysis. Alignments were extended in silico at their 3’-ends to a length of 200 bp and assigned to 32-nt bins along the genome. The resulting histograms (genomic “signal maps”) were stored in bigWig files. Peaks were identified using the MACS 2.1.0 algorithm at a cut off of p-value 1e-7, without control file, and with the –nomodel option. Peaks that were on the ENCODE blacklist of known false ChIP-Seq peaks were removed. Signal maps and peak locations were used as input data to Active Motifs proprietary analysis program, which creates Excel tables containing detailed information on sample comparison, peak metrics, peak locations and gene annotations. For differential analysis, reads were counted in all merged peak regions (using Subread), and the replicates for each condition were compared using DESeq2. Conclusions: Our study represents a detailed analysis of naive and activated pDC chromatin that analyzes the global murine TF reservoir as defined by Hu et al. in the AnimalTFdb (Hu et al. , 2019, Nucleic Acids Res 47, D33-D38). Our results show that pDC activation substantially altered the chromatin structure making it more or less accessible to specific TF families.

Project description:Purpose: this study is to analyze the chromatin landscape of H3R2mes in Plasmodium falciparum. Methods: In this study, H3R2me2s enrichment in the chromatin of wildtype parasite at schizont stage was analyzed by Cleavage Under Targets and Tagmentation (CUT&Tag) coupled with next generation sequencing (CUT&Tag-seq). Synchronized WT 3D7 at 40–46 hpi schizonts were harvested and fixed with 1% formaldehyde for 1 min at room temperature, followed by lysis with 0.06% saponin. The parasite pellets were suspended in 100 μl nuclear extraction buffer (20 mM HEPES–KOH pH 7.9, 10 mM KCl, 0.1% Triton X-100, 20% Glycerol, 0.5 mM Spermidine, 1x EDTA-free Protease Inhibitor cocktail). Ten μl of activated Concanavalin A-coated magnetic beads (EpiCypher # 21-1401) were added to each sample (~0.5 × 106 nuclei) and incubated for 10 min. The bead-bound nuclei were resuspended in 50 μl Antibody150 buffer (20 mM HEPES, pH 7.5, 150 mM NaCl, 0.5 mM spermidine, 1× protease inhibitor cocktail, 0.01% digitonin, 2 mM EDTA) containing 0.5 μg of rabbit anti-H3R2me2s (Epigentek #A-3705-050) as the primary antibody or rabbit IgG (Cell Signaling Technology #2729S) serving as a control. The primary antibody was then removed, and nuclei were then incubated with 0.5 μg of the secondary antibodies in 50 μl of Digitonin150 buffer (Antibody150, no EDTA) at room temperature for 30 min. The secondary antibodies were mouse anti-rabbit IgG (Invitrogen #31213). The nuclei were washed thrice with 200 μl Digitonin150 Buffer for 5 min to remove unbound antibodies and finally resuspended in 50 μl Digitonin300 Buffer (Digitonin150 but with 300 mM NaCl). Then, 2.5 μl of CUTANA pAG-Tn5 (EpiCypher #15-1017) were added to each reaction at room temperature for 1 h. The nuclei were washed thrice for 5 min in 200 μl Digitonin300 Buffer to remove the unbound pA-Tn5. Next, the nuclei were resuspended in 50 μl Tagmentation buffer (10 mM MgCl2 in Digitonin300) and incubated at 37 °C for 1 h. The beads were washed with 50 µl TAPS buffer (10 mM TAPS, pH 8.5, 0.2 mM EDTA), mixed with 5 µL SDS release buffer (10 mM TAPS pH 8.5; 0.1% SDS) to quench tagmentation, and then incubated for 1 hr at 58ºC to release tagmented chromatin into solution. Finally, 15 µl of 0.67% Triton-X was added to each reaction to quench SDS. PCR with appropriate barcoded primers was performed using the CUTANA High Fidelity 2x PCR Master Mix (EpiCypher #15-1018) according to the manufacturer's recommendations. Amplified DNA libraries were captured by incubating with 1.3 × Kapa pure beads (Roche #KK8001) according to the manufacturer's recommendations, and next-generation sequencing was performed on the NextSeq 550 platform. The reads of CUT&Tag-seq from three biological replicates were mapped to the P. falciparum genome (PlasmoDB Release 39.0) by using BWA (Li and Durbin 2009) after FastQC quality control. The peak calling was finished by MACS2 version 2.2.7.1 with parameters ‘callpeak -f BAMPE’ and a q-value cutoff of 0.05. Results: The three replicates of CUT&Tag-seq using nuclei from the schizont stage showed high reproducibility, with correlation coefficients of ~0.8. Peak calling using criteria of presence in at least two of three replicates with at least 50% overlap of the peaks identified 1629 H3R2me2s signals, distributed among the 14 chromosomes. Among these peaks, 57% (927) are localized at 5’ UTR regions of 791 genes, 35% (577) at coding regions of 470 genes, and 8% (125) at 3’ UTR regions of 115 genes. The peaks are ~17.44 bp wide and ~1265 bp from the ATG sites. Comparing the transcriptome data showed genes with H3R2me2s enrichment in the 5’ UTRs showed significantly higher expression than other genes in the genome, suggesting that H3R2me2s is associated with gene activation. In addition, H3R2me2s peaks were highly co-localized with the active mark H3K9Ac, H2A.Z, and H3K4me3, further implying H3R2me2s as a euchromatin mark. Gene ontology (GO) enrichment analysis revealed a multitude of cellular pathways, including merozoite invasion, transcription, translation, stress response, cell cycle, schizogony, cell adhesion, exit from RBC, vesicle transport, signal transduction, DNA repair, and telomere organization, which are potentially regulated by this euchromatic mark. Conclusions: Collectively, H3R2me2s is a active chromatin mark and regulates invasion and other important processes in human malaria parasite.

Project description:Purpose: The goals of this study are to identify BATF binding sites in purified BM-d Flt3-L cultured pDCs (ChIP-seq) at steady state and at 2h after CpG activation. Methods: Cells were fixed with 1% formaldehyde for 15 min and quenched with 0.125 M glycine, and sent to Active Motif Services (Carlsbad, CA) to be processed for ChIP-Seq. In brief, chromatin was isolated by the addition of lysis buffer, followed by disruption with a Dounce homogenizer. Lysates were sonicated and the DNA sheared to an average length of 300-500 bp. Genomic DNA (Input) was prepared by treating aliquots of chromatin with RNase, proteinase K and heat for de-crosslinking, followed by ethanol precipitation. Pellets were resuspended and the resulting DNA was quantified on a NanoDrop spectrophotometer. Extrapolation to the original chromatin volume allowed quantitation of the total chromatin yield. An aliquot of chromatin (20 µg, spiked-in with 200 ng of Drosophila chromatin) was precleared with protein A agarose beads (Invitrogen). Genomic DNA regions of interest were isolated using 4 ug of antibody against BATF (CST, 8638BF). Antibody against H2Av (0.4 ug) was also present in the reaction to ensure efficient pull-down of the spike-in chromatin (Egan et al., 2016). Complexes were washed, eluted from the beads with SDS buffer, and subjected to RNase and proteinase K treatment. Crosslinks were reversed by incubation overnight at 65 °C, and ChIP DNA was purified by phenol-chloroform extraction and ethanol precipitation. Quantitative PCR (QPCR) reactions were carried out in triplicate on specific genomic regions using SYBR Green Supermix (Bio-Rad). The resulting signals were normalized for primer efficiency by carrying out QPCR for each primer pair using Input DNA. Results: For ChIP Sequencing Illumina sequencing libraries were prepared from the ChIP and Input DNAs by the standard consecutive enzymatic steps of end-polishing, dA-addition, and adaptor ligation. Steps were performed on an automated system (Apollo 342, Wafergen Biosystems/Takara). After a final PCR amplification step, the resulting DNA libraries were quantified and sequenced on Illumina’s NextSeq 500 (75 nt reads, single end). Reads were aligned consecutively to the mouse genome (mm10) and to the Drosophila genome (dm3) using the BWA algorithm (default settings). Duplicate reads were removed and only uniquely mapped reads (mapping quality >= 25) were used for further analysis. The number of mouse alignments used in the analysis was adjusted according to the number of Drosophila alignments that were counted in the samples that were compared. Mouse alignments were extended in silico at their 3’-ends to a length of 200 bp, which is the average genomic fragment length in the size-selected library, and assigned to 32-nt bins along the genome. The resulting histograms (genomic “signal maps”) were stored in bigWig files. Peak locations were determined using the MACS algorithm (v2.1.0) with a cutoff of p-value = 1e-7. Peaks that were on the ENCODE blacklist of known false ChIP-Seq peaks were removed. Signal maps and peak locations were used as input data to Active Motifs proprietary analysis program, which creates Excel tables containing detailed information on sample comparison, peak metrics, peak locations and gene annotations. The results were further visualized using Integrative Genomics Viewer (IGV) (Robinson et al., 2011) and modified with Inkscape. Conclusions: Our study represents a detailed analysis of global BATF binding sites in naive and activated pDCs. Our results show that BATF binds not only to promoter regions of genes but extensively to enhancer elements as well. We identify key role players important for pDC biology that are regulated by BATF binding onto their DNA.

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ATAC-Seq of Batf-deficient pDC Transcriptomes (CpG 0h, 2h)

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