"This is an important finding because, during cancer development, many CpG islands are subjected to extensive methylation while the bulk of the genomic DNA becomes hypomethylated," Botcheva said. "These major epigenetic changes may contribute to the differences observed in the p53-binding-sites' distribution in normal and cancer cells."
The scientists say this study clearly illustrates that the genomic landscape the DNA modifications and the associated chromatin changes have a significant effect on p53 binding. Furthermore, it greatly extends the list of experimentally defined p53 binding sites and provides a general framework for investigating the interplay between transcription factor binding, tumor suppression, and epigenetic changes associated with cancer development.
This research, which was funded by the DOE Office of Science, lays groundwork for further advancing the detailed understanding of radiation effects, including low-dose radiation effects, on the human genome.
The research team also includes John Dunn and Carl Anderson of Brookhaven Lab, and Richard McCombie of Cold Spring Harbor Laboratory, where the high-throughput Illumina sequencing was done.
Methodology
The p53 binding sites were identified by a method called ChIP-seq: for chromatin immunoprecipitation (ChIP), which produces a library of DNA fragments bound by a protein of interest using immunochemistry tools, followed by massively parallel DNA sequencing (seq) for determining simultaneously millions of sequences (the order of the nucleotide bases A, T, C and G in DNA) for these fragments.
"The experiment is challenging, the data require independent experimental validation and extensive bioinformatics analysis, but it is indispensable for high-throughput genomic analyses," Botcheva said. Establishing such capability at BNL is directly related to the eff
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| Contact: Karen McNulty Walsh kmcnulty@bnl.gov 631-344-8350 DOE/Brookhaven National Laboratory Source:Eurekalert |