Source Code: Discovering the links between epigenetic tags

UNC researchers discover the first link between epigenetic tags—the chemicals that orchestrate how our genes are expressed and our health maintained or derailed.

From UNC Endeavors

Each of our cells contains genes that are the building blocks for life, but to keep a human healthy, those building blocks need to be manipulated in specific ways. This is where epigenetic tags come into play. These tags overlay our DNA and trigger the chemical reactions that manipulate our genes. If our genes aren’t expressed properly, then diseases—including many kinds of cancers—can be the result.

Scientists have long wondered whether some epigentic tags interact with each other. And if so, how?

Now, UNC researcher Brian Strahl has found the first evidence of a connection between two tags—histone modification and DNA methylation. And he found that a protein implicated in cancer plays a role in the proper maintenance of each tag.

Histones are proteins that control how DNA is packaged inside cells and how active genes will be. DNA methylation is the chemical process responsible for turning specific genes on or off. Both tags have to be regulated. And because each tag plays a specific role during different phases of cell division, some scientists didn’t think a single protein would play a role in maintaining both tags.

But using a lab technique he developed, Strahl found that a protein called UHRF1 helps maintain histone modification and DNA methylation. Strahl says he didn’t expect this result because scientists had thought that DNA methylation was maintained only during DNA replication.

The finding gives scientists more information about how epigenetic code is maintained and possibly how cancers are created.

Like all genes, the gene that makes UHRF1 is supposed to produce a specific amount of the protein. But other scientists have found that UHRF1 is overexpressed in some cancerous tumors. Because of Strahl’s finding, scientists now know that too much UHRF1 can cause trouble not only in histone modification but also with DNA methylation.

Strahl has given other researchers another bit of knowledge they can use to battle tumors where UHRF1 seems to be a culprit.


Brian Strahl, an associate professor of biochemistry and biophysics in the School of Medicine, published his research in the journal Nature Structural & Molecular Biology. Study co-authors were postdoc Scott B. Rothbart, research assistant professor Krzysztof Krajewski, and former UNC grad student Jorge Y. Martinez.