Project description:5′ methylation of cytosines in DNA molecules is an important epigenetic mark in eukaryotes. Bisulfite sequencing is the gold standard of DNA methylation detection, and whole-genome bisulfite sequencing (WGBS) has been widely used to detect methylation at single-nucleotide resolution on a genome-wide scale. However, sodium bisulfite is known to severely degrade DNA, which, in combination with biases introduced during PCR amplification, leads to unbalanced base representation in the final sequencing libraries. Enzymatic conversion of unmethylated cytosines to uracils can achieve the same end product for sequencing as does bisulfite treatment and does not affect the integrity of the DNA; enzymatic methylation sequencing may, thus, provide advantages over bisulfite sequencing.
Project description:To investigate the specificity of the Tn5 transposome with short adaptor DNAs under the non-crosslinked condition, we conducted ATAC-seq using alternative 19 bp adaptor DNAs (IE and OE) harboring 7 nucleotide differences between them (Maggie.JMB.1998), which allowed for specific PCR amplification without losing the superior enzymatic activity.
Project description:We have designed a method for direct measurement of in vitro noise. Using a synthetic STR sequencing library, we have measured the stutter patterns at various levels of PCR amplification during targeted amplification and library preparation processes
Project description:To investigate the cytogenetic and large-scale chromosomal changes in involuted or non-involuted microGISTs using post-whole genome amplification (WGA) FFPE DNA materials
Project description:Purpose: More than 90% of children with diffuse intrinsic pontine glioma (DIPG) die within 2 years of diagnosis. There is a dire need to identify therapeutic targets, however lack of patient material for research has limited progress. We evaluated a large cohort of diffuse intrinsic pontine gliomas (DIPGs) to identify recurrent genomic abnormalities and gene expression signatures underlying DIPG. Patients and Methods: We used single nucleotide polymorphism arrays to evaluate genomic copy number imbalances in 43 DIPGs from 40 patients and in 8 low-grade exophytic brainstem gliomas. Gene expression arrays were used to evaluate expression signatures from 27 DIPGs, 6 low-grade exophytic brainstem gliomas and 66 low-grade gliomas arising outside the brainstem. Results: Frequencies of specific large-scale and focal imbalances varied significantly between DIPGs and pediatric glioblastomas outside the brainstem. Focal amplifications of genes within the receptor tyrosine kinase-Ras-PI3-kinase signaling pathway were found in 47% of DIPG, with PDGFRA and MET showing the highest frequency. 30% of DIPG contained focal amplifications of cell-cycle regulatory genes controlling RB phosphorylation, and 21% had concurrent amplification of genes from both pathways. Some tumors showed heterogeneity in amplification patterns. DIPGs showed distinct gene expression signatures relating to developmental processes compared to pediatric glioblastomas arising outside the brainstem, while expression signatures of low-grade exophytic brainstem gliomas were similar to low-grade gliomas outside the brainstem.
Project description:Only a minuscule fraction of long non-coding RNAs (lncRNAs) are well characterized. The evolutionary history of lncRNAs can provide insights into their functionality, but comparative analyses have been precluded by our ignorance of lncRNAs in non-model organisms. Here, we use RNA sequencing to identify lncRNAs in eleven tetrapod species and we present the first large-scale evolutionary study of lncRNA repertoires and expression patterns. We identify ~11,000 primate- specific lncRNA families, which show evidence for selective constraint during recent evolution, and ~2,400 highly conserved lncRNAs (including ~400 genes that likely originated more than 300 million years ago). We find that lncRNAs, in particular ancient ones, are generally actively regulated and may predominantly function in embryonic development. lncRNA X-inactivation patterns reveal an extremely female-biased monotreme-specific lncRNA, which may partially compensate X-dosage in this lineage. Most lncRNAs evolve rapidly in terms of sequence and expression levels, but global patterns like tissue specificities are often conserved. We compared expression patterns of homologous lncRNA and protein-coding families across tetrapods to reconstruct an evolutionarily conserved co-expression network. This network, which surprisingly contains many lncRNA hubs, suggests potential functions for lncRNAs in fundamental processes like spermatogenesis or synaptic transmission, but also in more specific mechanisms such as placenta growth suppression through miRNA production.
