Scientists Describe Structural Basis of DNA's 'Second Code'

Findings Published in Nature

26-Jul-2004

Orion Genomics, a "second code" biotechnology company developing and commercializing oncology diagnostic products, announced that research conducted by the company's scientific co-founder Rob Martienssen, professor at Cold Spring Harbor Laboratory, has advanced understanding of the epigenetic code or "second genetic code" and the relationship between epigenetic changes and diseases including cancer. As described in today's issue of the leading scientific journal Nature, Martienssen related epigenetic information to gene expression patterns over large parts of the Arabidopsis genome, a plant model system. His work validates the role of epigenetic information in determining gene activity, and debuts a powerful new microarray-based methylation profiling technology invented in his laboratory.

In the paper titled "Role of Transposable Elements in Heterochromatin and Epigenetic Control," Martienssen and his colleagues at Cold Spring Harbor Laboratory investigated how chromosomal modifications, including epigenetic information encoded in DNA as methylation patterns, are related to gene expression. The researchers found that changes in DNA methylation and associated modifications result in changes in gene expression. Such control of gene expression by methylation is carried out at the level of specific regions of repeated DNA, rather than over large chromosomal regions as previously believed, since even in strongly methylated regions, active genes were found in unmethylated "islands" of DNA. These modifications are correlated with small interfering RNA (siRNA) that may guide epigenetic modifications to the DNA sequence.

"Our research concerns the mechanism by which methylated DNA and other epigenetic information determines gene activity," said Martienssen, a Professor at Cold Spring Harbor Laboratory and co-founder of Orion Genomics. "Because of this 'second code', epigenetic changes are emerging as important defects in childhood diseases, as well as in cancer. The profiling technology described in this paper will help to uncover these epigenetic defects, providing biomarkers and leads for potential therapy."

The technology used to determine methylation patterns was invented by Martienssen and his collaborators, exclusively licensed by Orion Genomics, and is marketed under the name MethylScope(TM) for the discovery of proprietary cancer biomarkers and the development of oncology diagnostic products. Abnormal methylation patterns are associated with the majority of all cancers, and the ability to determine them on a genome-wide basis has resulted in Orion's ongoing development of early noninvasive tests for cancer, which may enable earlier and more effective treatment and improve the cost, power and efficiency of clinical trials.

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