Difference between revisions of "IC4R006-Epigenomic-2016-22110044"

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(The Background of This Project)
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==The Background of This Project==
 
==The Background of This Project==
*Cytosine DNA methylation is a conserved epigeneti silencing mechanism in higher eukaryotes. Cytosine methylation plays an important role in many biological processes, including defense against transposon proliferation (Tsukahara et al., 2009), control of genomic imprinting (Morison et al., 2005) and regulation of gene expression (Bird, 2002). In mammals, cytosine methylation is controlled by the de novo methyltransferases DNMT3a/b, and is maintained by the methyltransferase DNMT1 (Goll and Bestor, 2005). Methylated cytosines occur almost exclu- sively at CG dinucleotides in mammalian genomes. However, Lister et al. (2009) recently showed that approximately 15% of methylated cytosines are associated with neighbor.
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* The identification and functional characterization of the regula- tory DNA elements is essential for understanding the regulation of gene expression in eukaryotic genomes. Although the genomes of an increasing number of eukaryotic species have been sequenced, genome-wide identification of regulatory DNA elements, such as that being done in the ENCODE project (The ENCODE Project Consortium 2007) and the Epigenomics Roadmap (Bernstein et al. 2010) in humans and in the modENCODE projects in Caenorhabditis elegans and Drosophila melanogaster (Gerstein et al. 2010; Roy et al. 2010), has been initiated only in few species. Active regulatory DNA elements, such as promoter and enhancers, in- teract with regulatory proteins. As a result, these regions are either free of nucleosomes or are under dynamic nucleosome modifications or displacements (Henikoff et al. 2009; Jin et al. 2009). Thus, active DNA elements are associated with ''open chromatin'' in higher eukaryotic genomes. One distinct characteristic of the genomic regions of open chromatin is a pronounced sensitivity to cleavage of endonuclease DNase I (Wu 1980; Keene et al. 1981; McGhee et al. 1981). Almost all active regulatory elements, in- cluding promoters, enhancers, suppressors, insulators, and locus control regions, have been shown to be marked by DNase I hypersensitive (DH) sites. (Gross and Garrard 1988).
* Despite significant interest in mapping cytosine methylation in various model eukaryotes, genome-wide mapping has only been accomplished in a few species. Mapping cytosine methylation at a single-base resolution has recently been accomplished in Arabidopsis thaliana (Cokus et al., 2008; Lister et al., 2008) and humans (Lister et al., 2009). The researchers are interested in the high-resolution mapping of DNA methylation associated with plant centromeres. Four of the 12 rice centromeres have been fully or nearly fully sequenced (Yan et al., 2008), providing an unprecedented opportunity to study the methylation associated with centromeric DNA in multicellular eukaryotes. The researchers conducted a methylcytosine immunoprecipitation (mCIP) combined with Illumina sequencing (mCIP-seq) assay in rice. We provide a genome-wide cytosine methylation map of rice and report on the dynamic methylation patterns associated with rice genes and centromeres.
 
  
 
==Labs working on this Project==
 
==Labs working on this Project==

Revision as of 04:38, 22 June 2016

Project Title

  • High-resolution mapping of open chromatin in the rice genome

The Background of This Project

  • The identification and functional characterization of the regula- tory DNA elements is essential for understanding the regulation of gene expression in eukaryotic genomes. Although the genomes of an increasing number of eukaryotic species have been sequenced, genome-wide identification of regulatory DNA elements, such as that being done in the ENCODE project (The ENCODE Project Consortium 2007) and the Epigenomics Roadmap (Bernstein et al. 2010) in humans and in the modENCODE projects in Caenorhabditis elegans and Drosophila melanogaster (Gerstein et al. 2010; Roy et al. 2010), has been initiated only in few species. Active regulatory DNA elements, such as promoter and enhancers, in- teract with regulatory proteins. As a result, these regions are either free of nucleosomes or are under dynamic nucleosome modifications or displacements (Henikoff et al. 2009; Jin et al. 2009). Thus, active DNA elements are associated with open chromatin in higher eukaryotic genomes. One distinct characteristic of the genomic regions of open chromatin is a pronounced sensitivity to cleavage of endonuclease DNase I (Wu 1980; Keene et al. 1981; McGhee et al. 1981). Almost all active regulatory elements, in- cluding promoters, enhancers, suppressors, insulators, and locus control regions, have been shown to be marked by DNase I hypersensitive (DH) sites. (Gross and Garrard 1988).

Labs working on this Project

  • Department of Horticulture, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA;
  • Department of Plant and Microbial Biology, University of California–Berkeley, Berkeley, California 94720, USA;
  • Institute for Genome Sciences and Policy, Duke University, Durham, North Carolina 27708, USA

Corresponding Author

  • Jiming Jiang (jjiang1@wisc.edu)