When a cell divides, it must first make a copy of its DNA, a fundamental step in the life cycle of cells that occurs billions of times a day in the human body. While scientists have had an idea of the molecular tools that cells use to replicate DNAthe enzymes that unzip the double-stranded DNA and create "daughter" copiesthey did not have a clear picture of how the process works.
Now, researchers at Rockefeller University have built the first model system to decipher what goes on at the "replication fork"the point where DNA is split down the middle in order to create two exact copies. The findings are specific to eukaryotic cells, the defining feature of which is that the DNA is contained within a nucleus. All multicellular life forms, including humans, are eukaryotes. The researchers' findings, which may have profound implications for the study of cell division and human disease, appeared July 6 in the journal Nature Structural and Molecular Biology.
"We were able to purify and reconstitute the central components that propel the eukaryotic replication fork, which for the first time enables us to study the process and its regulation by the cell in fine detail," says the paper's senior author Michael O'Donnell, head of the Laboratory of DNA Replication at Rockefeller University. "What is more exciting, I believe, is that this opens up replication-fork biology to biochemical study by many labs, providing a new tool to unravel some pressing questions in a number of fields of study, including epigenetics and DNA repair." O'Donnell is Anthony and Judith Evnin Professor at Rockefeller and a Howard Hughes Medical Institute investigator.
According to O'Donnell, the team's techniques may allow researchers to reconstruct at the molecular level biochemical events that are known to occur but were difficult or impossible to study in detail. For example, scientists know that epigenetic informationinheritable information that is not encoded b
|Contact: Franklin Hoke|