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Genome-wide identification of DNaseI hypersensitive sites using active chromatin sequence libraries
Peter J Sabo1, Richard Humbert, Michael Hawrylycz
1Department of Molecular Biology, Regulome, Canal View Building, 551 North 34th Street, Seattle, WA 98103, USA.
Summary
Researchers identified active chromatin sequences (ACSs) using DNaseI hypersensitive sites (HSs) in erythroid cells. This method maps regulatory elements, revealing open chromatin domains across the genome.
Area of Science:
- Genomics
- Molecular Biology
- Epigenetics
Background:
- Identifying transcriptional regulatory elements is crucial for understanding genome biology.
- DNaseI hypersensitivity indicates active regulatory regions like enhancers and promoters.
- Existing methods require refinement for genome-wide identification of these sites.
Purpose of the Study:
- To develop and apply a novel method for genome-scale identification of DNaseI hypersensitive sites (HSs).
- To analyze active chromatin sequences (ACSs) derived from erythroid cells to understand regulatory element distribution.
Main Methods:
- Developed an approach using isolation and cloning of in vivo DNaseI cleavage sites to create libraries of active chromatin sequences (ACSs).
- Analyzed over 61,000 ACSs from erythroid cell samples.
- Correlated ACS density with gene locations, CpG islands, and conserved noncoding sequences.
Main Results:
- Observed peaks in ACS density at transcriptional start sites and non-gene-associated CpG islands.
- Found ACS density paralleled DNaseI HS distribution.
- Demonstrated that ACSs and HSs are found near both expressed and non-expressed genes, indicating widespread open chromatin.
Conclusions:
- The developed ACS method enables genome-scale identification of active regulatory elements.
- A significant portion of genes are located within open chromatin domains.
- This approach allows for quantitative approximation of regulatory sequence distribution in the human genome.