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SRX5985670: GSM3861104: SOM-H3K27ac ChIP rep2; Caenorhabditis elegans; ChIP-Seq
1 ILLUMINA (Illumina Genome Analyzer II) run: 29.9M spots, 2.3G bases, 1Gb downloads

Submitted by: NCBI (GEO)
Study: Isolated C. elegans germ nuclei exhibit distinct genomic profiles of histone modification and gene expression
show Abstracthide Abstract
The wide variety of specialized permissive and repressive mechanisms by which germ cells regulate developmental gene expression are not well understood genome-wide. Isolation of germ cells with high integrity and purity from living animals is necessary to address these open questions, but no straightforward methods are currently available. Here we present an experimental paradigm that permits the isolation of nuclei from C. elegans germ cells at quantities sufficient for genomic analyses. We demonstrate that these nuclei represent a very pure population and are suitable for both transcriptome analysis (RNA-seq) and chromatin immunoprecipitation (ChIP-seq) of histone modifications. The method does not require specialized transgenic strains or growth conditions and can be readily applied with minimal troubleshooting. This new capacity removes a major barrier in the field to dissect gene expression mechanisms in the germ line of C. elegans. Consequent discoveries using this technology will be relevant to conserved regulatory mechanisms across species. Overall design: This series includes four ChIP-seq samples (IGN-H3K27ac and SOM-H3K27ac and IGN-H3K4me3 and SOM-H3K4me3) and two RNA-seq samples (IGN and SOM) performed in C. elegans. The ChIP-seq experiments were performed in duplicate with matching input for normalization, thus there are 16 ChIP-seq sequencing fastq files (8 ChIP and 8 input). The RNA-seq samples were done in duplicate, yielding two sequence files per sample, thus there are 4 RNA-seq sequencing fastq files. We are also submitting 4 combined normalized wig files for ChIP-seq samples (IGN-H3K27ac and SOM-H3K27ac and IGN-H3K4me3 and SOM-H3K4me3) and 4 bigwig files for RNA-seq (2 replicates of IGN RNA-seq and 2 replicates of SOM RNA-seq). Thus, we are submitting 20 fastq files (consisting of 16 fastq files for ChIP-seq and 4 fastq files for RNA-seq) and 8 wig/bigwig files for the series (consisting of 4 wig files for ChIP-seq and 4 bigwig files for RNA-seq).
Sample: SOM-H3K27ac ChIP rep2
SAMN11975699 • SRS4891122 • All experiments • All runs
Library:
Instrument: Illumina Genome Analyzer II
Strategy: ChIP-Seq
Source: GENOMIC
Selection: ChIP
Layout: SINGLE
Construction protocol: Growth: glp-1(q224) animals were cultured to starvation on NGM plates at 15°C. L1 worms were floated and plated on one 15-cm NGM plate. Worms were cultured at 15°C for four days until gravid. Adult worms were bleached and embryos were incubated with shaking at 15°C for 36-42 hours. L1s were plated to three peptone enriched plates with 50K L1s per plate and cultured at 25°C for 46-48 hours until adult stage. Adult glp-1(q224) animals were harvested by 3X washes with M9. Extraction: Worms were crosslinked in 50 mL 2% formaldehyde for 30 minutes in a 50 mL conical tube at room temperature. Formaldehyde was quenched by 1 M Tris (pH 7.5) wash. Worms were then washed 2 more times with M9. Worms were transferred to a 15 mL conical tube and washed with 15 mL prechilled FA buffer. Worm pellets were frozen in liquid nitrogen and stored at -80°C. Worm pellets were thawed on ice and 750 µl of FA buffer was added to each sample. Samples were transferred to a 2 mL Kontes Dounce. Samples were Dounced 15 times with the small â??Aâ? pestle for two cycles and 15 times with the large â??Bâ? pestle for four cycles. Samples were sonicated with a SFX250 sonifier in an ice bath at 22% amplitude with 10 sec on/1 min off pulses for 34 cycles. 100-650 bp DNA fragments were enriched after sonication. 4.4 mg protein was used for each ChIP sample. 5% of lysate was removed for input sample and stocked at -20°C overnight. 5 μg of anti-H3K27ac was used for each SOM sample. Library construction: The Yale Center for Genome Analysis (YCGA) prepared the library and performed sequencing. The KAPA Hyper Library Preparation kit was used for ChIP sequencing library prep. DNA fragment ends were repaired with T4 DNA Polymerase, and Polynucleotide Kinase and â??Aâ? base added using Klenow fragment in a single reaction followed by ligation of custom adapters (IDT) using T4 ligase. Adaptor-ligated DNA fragments were purified and size selected with Agencourt AMPure XP magnetic beads. Adaptor-ligated DNA fragments were amplified by LM-PCR using custom-made primers (IDT). During LM-PCR, unique 10 base indices were inserted at each DNA fragment and amplified products were purified.
Experiment attributes:
GEO Accession: GSM3861104
Links:
Runs: 1 run, 29.9M spots, 2.3G bases, 1Gb
Run# of Spots# of BasesSizePublished
SRR921497529,916,7452.3G1Gb2019-07-23

ID:
8021976

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