This erasure has direct implications for cancer research, says Niels Geijsen, Ph.D., lead author of the study and now a principal investigator at the Center for Regenerative Medicine and Technology at Massachusetts General Hospital. In certain tumors, he explains, imprints that tend to slow down growth and cell division have been lost, so cells grow out of control. "We hope to use these embryonic germ cells to study how the erasure process is initiated normally, and how it is disrupted in some cancers," he says.
Studying the imprints may also offer insights into the process of cloning, the researchers note. The cloning process, which involves transferring the nucleus of an adult cell into an egg, causes many of the parent-specific imprints to be lost. This loss is responsible for many of the abnormalities found in cloned animals.
Reprogramming cells
Embryonic germ cells may also aid in understanding the process of cell specialization. Most of an embryo's cells - and all adult cells - are programmed to specialize and create particular tissues and body parts via a separate set of gene modifications. But embryonic germ cells are the only cells within the developing organism to maintain the capacity to generate all tissues, also called pluripotency.
"We want to know how these cells are kept in their pristine state," says George Daley, M.D., Ph.D., senior investigator on the study and a stem cell biologist now at Children's Hospital Boston and Harvard Medical School. "This may teach us about how we can reverse the process and reprogram adult cells back to their embryonic state."
A better understanding of how these gene modifications are programmed may come from studying the parent-specific imprints, and may have implications for therap
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Contact: Mary Ellen Shay
mary.Shay@tch.harvard.edu
617-355-6420
Children's Hospital Boston
10-Dec-2003