The study, done in yeast, should help researchers better understand how human cells cram more than 7 feet of DNA--the total length of the genetic material in our 46 chromosomes--into the nucleus, the tiny capsule that holds the chromosomes inside the cell.

The study was published in the April 23 issue of the journal Molecular Cell.

The protein, known as Hif1p, works in conjunction with an enzyme complex to add histone proteins to newly made DNA. Histones are proteins that form tiny spools around which DNA is wound during packaging. The combination of DNA and its proteins is known as chromatin.

"DNA is the brains behind all that happens in a cell," says lead investigator Dr. Mark R. Parthun, assistant professor of molecular and cellular biochemistry and a researcher with The Ohio State University Comprehensive Cancer Center Arthur G. James Cancer Hospital and Richard J. Solove Research Institute.

"So the packaging of DNA into chromatin is very important for controlling what goes on in the cell."

For example, certain stretches of DNA must be reachable at certain times to control cell division and to turn genes on or off.

"If the DNA isn't properly packaged, that's not going to work right," he says.

The proper packaging of DNA is important for cancer cells, too. Cancer is caused by unrestricted cell division. Parthun's research might therefore help lead to drugs that can block this process and lead to new cancer therapies.

The biochemical pathways that cells use to package DNA in the nucleus remain poorly understood. In 1996, Parthun discovered an enzyme complex in yeast that cells use to assemble histones. He found that the enzyme, known as a type-B histone acetyltransferase (composed of the proteins Hat1p and Hat2p), modifi
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Contact: Darrell E. Ward
Ward-15@medctr.osu.edu
614-293-3737
Ohio State University
30-Apr-2004