The pan-cancer analysis of whole genomes The expansion of whole-genome sequencing studies from individual ICGC and TCGA working groups presented the opportunity to undertake a meta-analysis of genomic features across tumour types. To achieve this, the PCAWG Consortium was established. A Technical Working Group implemented the informatics analyses by aggregating the raw sequencing data from different working groups that studied individual tumour types, aligning the sequences to the human genome and delivering a set of high-quality somatic mutation calls for downstream analysis (Extended Data Fig. 1). Given the recent meta-analysis
SUMMARY
Sarcomas are a broad family of mesenchymal malignancies exhibiting remarkable histologic diversity. We describe the multi-platform molecular landscape of 206 adult soft tissue sarcomas representing 6 major types. Along with novel insights into the biology of individual sarcoma types, we report three overarching findings: 1) unlike most epithelial malignancies, these sarcomas (excepting synovial sarcoma) are characterized predominantly by copy number changes, with low mutational loads and only a few genes (TP53, ATRX, RB1) highly recurrently mutated across sarcoma types, 2) within sarcoma types, genomic and regulomic diversity of driver pathways defines molecular subtypes associated with patient outcome, and 3) the immune microenvironment, inferred from DNA methylation and mRNA profiles, associates with outcome and may inform clinical trials of immune checkpoint inhibitors. Overall, this large-scale analysis reveals previously unappreciated sarcoma type-specific changes in copy number, methylation, RNA, and protein, providing insights into refining sarcoma therapy and relationships to other cancer types.
Eviction or destabilization of nucleosomes from chromatin is a hallmark of functional regulatory elements of the eukaryotic genome. Historically identified by nuclease hypersensitivity, these regulatory elements are typically bound by transcription factors or other regulatory proteins. FAIRE (Formaldehyde-Assisted Isolation of Regulatory Elements) is an alternative approach to identify these genomic regions and has proven successful in a multitude of eukaryotic cell and tissue types. Cells or dissociated tissues are crosslinked briefly with formaldehyde, lysed, and sonicated. Sheared chromatin is subjected to phenol-chloroform extraction and the isolated DNA, typically encompassing 1-3% of the human genome, is purified. We provide guidelines for quantitative analysis by PCR, microarrays, or next-generation sequencing. Regulatory elements enriched by FAIRE display high concordance with those identified by nuclease hypersensitivity or ChIP, and the entire procedure can be completed in three days. FAIRE exhibits low technical variability, which allows its use in large-scale studies of chromatin from normal or diseased tissues.
SUMMARY
Posttranslational modifications (PTMs) of tubulin specify microtubules for specialized cellular functions and comprise what is termed a “tubulin code”. PTMs of histones comprise an analogous “histone code”, although the “readers, writers and erasers” of the cytoskeleton and epigenome have heretofore been distinct. We show that methylation is a PTM of dynamic microtubules, and that the histone methytransferase, SETD2, which is responsible for H3 lysine 36 trimethylation (H3K36me3) of histones, also methylates α-tubulin at lysine 40, the same lysine that is marked by acetylation on microtubules. Methylation of microtubules occurs during mitosis and cytokinesis, and can be ablated by SETD2 deletion, which causes mitotic spindle and cytokinesis defects, micronuclei and polyploidy. These data now identify SETD2 as a dual function methyltransferase for both chromatin and the cytoskeleton, and show a requirement for methylation in maintenance of genomic stability and the integrity of both the tubulin and histone codes.
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