REVEALING THE SECRETS OF GENES
LSU biologist studies the activation of genetic codes in DNA

DNA from a single human cell is more than two meters in length when stretched out in a line. But inside cells, the familiar double-helix of genetic information is tightly packaged. In actuality, DNA does not appear laid out in strands but wrapped around spools of histones, a type of protein found in the nuclei of cells. This complex of DNA and its associated proteins is known as chromatin, which regulates how many genes function.

A team of researchers, led by LSU assistant professor of biological sciences David Donze, is studying how chromatin fulfills its role as a genetic regulator in cells. Chromatin operates the on-off switch for sections of genetic code. Donze and his team are conducting experiments with yeast cells – used for their similarity to human cells and fast growth-rate – to learn more about the process of turning these genes on and off and exploring a feature of chromatin known as a boundary element.

Boundary elements serve as road blocks that separate different sections of genetic activity and keep them from interfering with one another. If one section is in an active state, these road blocks allow adjacent segments to function independently, so that they may be either active or inactive as determined by their chromatin and remain uninfluenced by the neighboring sections.

By understanding how boundary elements and chromatin function, researchers are making progress towards learning how to turn parts of our genetic code on and off as needed. When genes are added to cells, they often become inactivated due to the local chromatin structure where they land. If small enough boundary elements can be uncovered, then researchers may be able to buffer genes that they want to add into chromosomes so that they are not affected by surrounding chromatin in adverse ways. This could have great impact on fields like gene therapy, which is still in experimental stages. If Donze’s research proves successful, these concepts could be used to make gene therapy a more stable and reliable option, allowing therapists to correct genetic errors more securely without having to worry that corrections may be temporary or create further problems inadvertently.

Chromatin and boundary elements may also prove important to the study of cancer. Often, some types of cancer are regarded as the result of mutations within the body’s cells. Donze and his team believe there may be another cause.

“Cancer may not always be a mutation like we commonly think,” says Donze. “It’s possible that some kinds of cancer may be the result of alterations in chromatin-mediated gene regulation.”

If chromatin’s structure is changed or boundary elements fail, it is possible that these changes may eventually manifest as what we call cancer. If these kinds of alterations can be pinpointed, it may be possible to identify what caused them or perhaps even introduce new genes or boundary elements to correct the errors that have taken place. As researchers make further steps into understanding the role of chromatin, we learn more about what makes our genes work and how to repair them.

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from Summer 2006 Issue