An important step in the effort to compile a complete catalogue of functional elements in the human genome is to be published in Nature Genetics. A specific chemical signature of DNA sequences that promote the expression of nearby genes has been identified, and researchers should now be able to more accurately predict the location and function of these sequences.
Analysis of the complete sequence of the human genome has identified approximately 25,000 genes, but genes comprise only a small fraction of the genome. At least some of the remainder of the genome consists of sequences called promoters and enhancers that determine when, where, and to what extent each of these genes will be expressed. While promoters are typically found immediately adjacent to genes, enhancers can be located much further away, making it difficult to identify them.
Bing Ren and colleagues examined 1% of the human genome and catalogued a number of different chemical modifications that are made to histones, which are proteins that bind to and package DNA, and are known to be involved in gene regulation. They found that the histones bound to known promoters are marked by chemical modifications that are distinct from those found on histones bound to enhancers. This information enabled the authors to accurately predict the location and function of promoters and enhancers that were independently identified, as well as identify a previously undiscovered enhancer.
Bing Ren (Ludwig Institute for Cancer Research, La Jolla, CA, USA)
Abstract available online.
(C) Nature Genetics press release
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