14 DAY TRIAL // Each cell contains the entire DNA code, but only small portions of it are activated. As a consequence the cell has a certain function instead of others. But what determines which genes are to be activated? This has been longstanding enigma.
Each gene in the DNA code is responsible for the production of a certain protein. Activating certain genes instead of others leads to the production of a particular set of proteins and this in turn leads to the cell having a certain specific function - for example becoming a muscle cell instead of a skin cell. But what activates the genes? Scientists have now found that the activation mechanism involves the RNA using certain proteins.
The study was conducted by Frank Sauer, a biochemistry professor at Unifersity of California, Riverside together with Elisabeth Kremmer of the Institut f?r Molekulare Immunologie in Munich, and fellow UCR researchers Tilman Sanchez-Elsner and Dawei Gou. They have studied how certain proteins, known as epigenetic activators (such as Ash1), work in the fruit fly Drosophila.
"The fact that these epigenetic activators, such as Ash1, turn on the expression of specific target genes has been known for some time. However, the mechanisms by which epigenetic activators recognize and bind these target genes was not yet known", Sauer said. "What we were able to show is that the epigenetic activator Ash1 is recruited to a target gene through cell-type specific non-coding RNA."
They have found that the activator Ash1 binds to a certain DNA elements inside the targeted gene. The process is guided by RNA molecules which are produced by the DNA elements themselves. The RNA attracts the activators. More specifically, Ash1 binds to the Trithorax-reponse elements (TREs), located inside the gene Ultrabithorax (Ubx). Non-coding RNA is produced by and retained at the TREs of Ubx. The RNA attracts Ash1 to the TREs and thus helps activating the expression of the Ubx gene.
"As a result, we can now use non-coding RNAs as tools to actively determine cell fate," Sauer said. "Over the last few years, researchers have focused on how non-coding RNAs silence genes," said Anthony Carter, of the National Institute of General Medical Sciences, which partially funded the research. "Dr. Sauer's work has revealed that non-coding RNAs have a broader range of functions than was previously known, and suggests a model for how they can help activate, rather than silence, a key regulator of animal development."
This study may help advance cancer and stem-cell research.