Project description:Targeted enrichment-based next-generation sequencing or whole exome sequencing were taken for patients with hypomyelinating leukodystrophies to reveal genetic aetiologies. All genomic DNA used in the experiments was extracted from the peripheral leukocytes. A complete kit was synthetized using the Agilent SureSelect Target Enrichment technique, capturing the coding regions from 104 candidate genes, including their exons and exon-intron boundaries (11,473 probes, 383.065 kbp in total). The following NGS which included equipment and reagents was performed on an Illumina NEXTSEQ500 platform manufactured by Illumina (San Diego, California, USA) using paired-end sequencing of 110 bp. The clean paired-end reads were aligned to the human reference genome build hg19, which was previously annotated using ANNOVAR, in addition to insertion-deletion (indel) and single-nucleotide polymorphism (SNP) calling.
Project description:Targeted enrichment-based next-generation sequencing or whole exome sequencing were taken for patients with hypomyelinating leukodystrophies to reveal genetic aetiologies. All genomic DNA used in the experiments was extracted from the peripheral leukocytes. A complete kit was synthetized using the Agilent SureSelect Target Enrichment technique, capturing the coding regions from 104 candidate genes, including their exons and exon-intron boundaries (11,473 probes, 383.065 kbp in total). The following NGS which included equipment and reagents was performed on an Illumina NEXTSEQ500 platform manufactured by Illumina (San Diego, California, USA) using paired-end sequencing of 110 bp. The clean paired-end reads were aligned to the human reference genome build hg19, which was previously annotated using ANNOVAR, in addition to insertion-deletion (indel) and single-nucleotide polymorphism (SNP) calling.
Project description:Microarray-based enrichment of selected genomic loci is a powerful method for genome complexity reduction. Since the vast majority of exons in vertebrate genomes are smaller than 150 nt, we have explored the use of short fragment libraries (85-110bp) to achieve higher enrichment specificity by reducing carryover and adverse effects of flanking intronic sequences. These short fragment libraries were enriched for 1.69 Mb of exonic sequences, using custom 244K microarrays, and sequenced using AB/SOLiD. High enrichment specificity (60 M-bM-^@M-^S 75%) was obtained at 67-213x average coverage, with 77-92% and 90-98% of targeted regions covered with more than 25% and 10% of the average coverage, respectively. As a more appropriate measure of the evenness of coverage, which is relatively independent of sequencing depth, we introduce the evenness of coverage parameter E. E values up to 75% were achieved. To verify the accuracy of SNP/mutation detection we evaluated 384 known non-reference SNPs in the targeted regions. At ~ 200x average sequence coverage, we were able to survey 96.4% of 1.69 Mb of genomic sequence with only 4.2% false negative calls while 3.6% of targeted regions were marked as unsurveyed. A total of 1197 new variants were detected. Verification revealed only 8 false positive calls, resulting in an overall false positive rate of less than 1 per ~200,000 bp (0.0005%, equivalent to an overall phred score of 55). 4 samples + capture design file
Project description:Targeted sequencing of genome is essential to the basic biological research and biomedicine. Therefore, various targeted enrichment methods have been developed for this end, in which various hybridization-based methods have been most widely used. However, the current hybridization-based methods (both on solid or in solution) are still restricted by the intrinsic shortcomings of nucleic acid hybridization. In this study, by combining an engineered dCas9-sgRNA with widely used magnetic isolation, we developed a new strategy to enrich target genomic DNAs in high efficiency. In this strategy, target DNA was firstly specifically recognized and bound by a complex of dCas9 and capture sgRNA (csgRNA). The DNA-dCas9-csgRNA complex was then captured on magnetic beads through the annealing of elongated 3′ end of csgRNA with single-stranded capture oligonucleotides coupled on streptavidin-coated magnetic beads. We thus named the strategy as CRISPR-assistant target enrichment (CATE). The enriched DNAs can be analyzed by the next generation sequencing (NGS). We thus named the technique as CATE-seq. Used the technique, we successfully enriched 35 target exons of 6 genes in 6 cell lines by using 54 csgRNA. We found that the target genomic DNA fragments such as exons could be efficiently enriched and analyzed by CATE-seq. The technique has several significant advantages over the current hybridization-based methods, including high simplicity, specificity, sensitivity, and throughput. This study therefore provides a new powerful tool for targeted sequencing.
Project description:In continuation of our whole-exome and targeted sequencing study on non-muscle-invasive bladder cancer, we carried out this targeted paired tumour/blood sequencing study including 78 Ta stage bladder cancer patients. Agilent’s SureDesign tool was used to design a 1.133 Mb SureSelect custom capture for all coding exons of the 140 selected candidate genes.
Project description:Microarray-based enrichment of selected genomic loci is a powerful method for genome complexity reduction. Since the vast majority of exons in vertebrate genomes are smaller than 150 nt, we have explored the use of short fragment libraries (85-110bp) to achieve higher enrichment specificity by reducing carryover and adverse effects of flanking intronic sequences. These short fragment libraries were enriched for 1.69 Mb of exonic sequences, using custom 244K microarrays, and sequenced using AB/SOLiD. High enrichment specificity (60 – 75%) was obtained at 67-213x average coverage, with 77-92% and 90-98% of targeted regions covered with more than 25% and 10% of the average coverage, respectively. As a more appropriate measure of the evenness of coverage, which is relatively independent of sequencing depth, we introduce the evenness of coverage parameter E. E values up to 75% were achieved. To verify the accuracy of SNP/mutation detection we evaluated 384 known non-reference SNPs in the targeted regions. At ~ 200x average sequence coverage, we were able to survey 96.4% of 1.69 Mb of genomic sequence with only 4.2% false negative calls while 3.6% of targeted regions were marked as unsurveyed. A total of 1197 new variants were detected. Verification revealed only 8 false positive calls, resulting in an overall false positive rate of less than 1 per ~200,000 bp (0.0005%, equivalent to an overall phred score of 55).
Project description:Here, we report that ATRX co-localizes with the H3K9-methyl transferase SETDB1 (also known as ESET), the co-repressor TRIM28 (also known as KAP1), and the transcription factor ZNF274 at 3â exons of Zinc Finger Genes (ZNFs) containing an atypical H3K9me3/H3K36me3 chromatin signature. Disruption of ATRX and ZNF274 leads to a significant reduction of H3K9me3, particularly at the 3â ZNF exons and other atypical chromatin regions, higher percentages of DNA damage, and defects in cell cycle. Taken together, our studies suggest that ATRX binds the 3â exons of ZNFs to maintain genomic stability through the regulation of their H3K9me3 levels XL-MNase ChIP-seq of ATRX was performed in the erythroleukemic cell line K562 and the Neuroblastoma cell line LAN6. Two independent replicates using different ATRX antibodies were performed in K562. Additionally, Native ChIP-seq of H3K9me3 in LAN6, ATRX WT and ATRX KO K562 cells was performed. Input samples were sequenced as control.
Project description:Here, we report that ATRX co-localizes with the H3K9-methyl transferase SETDB1 (also known as ESET), the co-repressor TRIM28 (also known as KAP1), and the transcription factor ZNF274 at 3’ exons of Zinc Finger Genes (ZNFs) containing an atypical H3K9me3/H3K36me3 chromatin signature. Disruption of ATRX and ZNF274 leads to a significant reduction of H3K9me3, particularly at the 3’ ZNF exons and other atypical chromatin regions, higher percentages of DNA damage, and defects in cell cycle. Taken together, our studies suggest that ATRX binds the 3’ exons of ZNFs to maintain genomic stability through the regulation of their H3K9me3 levels
Project description:Single Gland Whole-exome sequencing: building on our prior description of multi-region WES of colorectal tumors and targeted single gland sequencing (E-MTAB-2247), we performed WES of multiple single glands from different sides (right: A and left: B) of two tumors in this study (tumor O and U) on the illumina platform using the Agilent SureSelect 2.0 or illumina Nextera Rapid Capture Exome kit (SureSelect or NRCE, as indicated in the naming of fastq files). Colorectal Cancer Xenograft Whole-exome sequencing: The HCT116 and LoVo Mismatch-Repair-deficient colorectal adenocarcinoma cell lines were obtained from the ATCC and cultured under standard conditions. For both cell lines, a single âfoundingâ cell was cloned and expanded in vitro to ~6M cells. Two aliquots of ~1M cells were subcutaneously injected into opposite flanks (right and left) of a nude mouse and tumors allowed to reach a size of ~1B cells (1cm3) before the animal was sacrificed. Tumor tissue was collected separately from the right and left lesions and DNA was extracted for WES using the illumina TruSeq Exome kit or Nextera Rapid Capture Exome expanded Kits (Truseq or NRCEe), as was DNA from the first passage population (a polyclonal tissue culture for HCT116 and a polyclonal xenograft sample for LoVo), which were employed as a control to study mutation accumulation in culture and post xenotransplantation.