Dataset Information

High-throughput sequencing of DNA G-quadruplex structures in the human genome

ABSTRACT: Nucleic acid secondary structures play a critical role in the regulation of biological processes. Genome-wide detection of DNA and RNA secondary structures is essential to identify pathways that are regulated by nucleic acid folding. There are no methods to interrogate DNA secondary structure formation on a genome-wide scale. We present G4-Seq, a method that applies the concept of polymerase interference at G-quadruplex (G4) DNA secondary structures to a human genome scale by massively parallel array-sequencing. Our approach generated a high-resolution map of more than 700,000 distinct G4s in the human genome, including non-canonical structural variants with bulges or extended loops, which are difficult to predict by classical approaches. This experimental map reveals many previously uncharacterized G4 structures in functional genomic regions, of which we highlight those associated with cancer, that include oncogenes, tumor suppressors and somatic copy-number alterations.

ORGANISM(S): Homo sapiens

PROVIDER: GSE63874 | GEO | 2015/07/19

SECONDARY ACCESSION(S): PRJNA269309

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:DNA secondary structures are important for fundamental genome functions such as transcription and replication1. The G-quadruplex (G4) structural motif has been linked to gene regulation2,3 and genome instability4,5 and may be important to cancer development and other diseases6-8. Recently, ~700,000 discrete G4s have been observed in naked human single-stranded genomic DNA using G4-seq, a high-throughput sequencing technique that detects structural features in vitro.9 It is of vital importance to investigate G4 structures within an endogenous chromatin context, which until now remained elusive10,11. Herein, we address this via the development of G4 ChIP-seq, an antibody-based G4 chromatin immunoprecipitation and high-throughput sequencing approach. We identified ~10,000 endogenous G4 structures and show that G4s are predominantly seen in regulatory, nucleosome-depleted, chromatin regions. G4s were enriched in the promoters and 5âUTR regions of highly transcribed genes, particularly in genes related to cancer and in somatic copy number amplifications, such as MYC. Reorganization of the chromatin landscape using a histone deacetylase inhibitor, resulted in de novo G4 formation in new and more prominent regulatory, nucleosome-depleted regions associated with increased transcriptional output. Our findings suggest a striking relationship between promoter nucleosome-depleted regions, G4 formation and elevated transcriptional activity. Comparison between normal human epidermal keratinocytes and their immortalized counterparts revealed a ï¾7-fold greater G4 abundance in immortalized cells, of which 80 % were found in regulatory, nucleosome-depleted regions common to both cell types. Consequently, cells exhibiting more G4s displayed significantly increased transcriptional output and were more sensitive to growth inhibition by a small molecule G4 ligand. Overall, our results provide new mechanistic insights into where and when DNA adopts G4 structure in vivo. Our findings show for the first time that regulatory, nucleosome-depleted chromatin and transcriptional states predominantly shape the endogenous G4 DNA landscape. Two cell lines, treated with entinostat or untreated, analyzed to detect gene expression differences, presence of G-Qudruplexes and chromatin state. Each combination of conditions replicated in duplicates or triplicates.

Dataset Information

High-throughput sequencing of DNA G-quadruplex structures in the human genome

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets