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 REPRODUCTIVE BIOLOGY: Ovaries Exhibit Ongoing Power to Produce Eggs
The idea that women are born with a finite pool of egg cells that age and die out at menopause has been entrenched in the minds of biologists for more than half a century. "Basically the dogma has been set in stone," said Jonathan Tilly (seated), who with Joshua Johnson, Jacqueline Canning, and colleagues reports a discovery in the March 11 Nature that topples this doctrine. They have found that mouse ovaries continually replenish their supply of oocytes. And using a variety of molecular markers, the researchers were able to demonstrate the existence of an as yet unidentified pool of germline stem cells.
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 BIOLOGICAL CHEMISTRY: Molecular Cowboy Seen Herding Actin Filaments
Formins are a group of proteins that guide the growth of actin filaments. X-ray crystallographic data just obtained by Michael Eck (seated), David Pellman, and colleagues at the Dana-Farber Cancer Institute, indicate that this activity depends on two formin monomers, or single subunits, being held tightly together by post-and-lasso-shaped peptide domains. The molecular chains directly attached to the lassos are flexible, allowing each subunit to slide relative to the other. Because of this action, Eck predicts that these dimers "stair step" along, leaving a growing chain of actin in their footsteps. The model and structure are published in the March 5 Cell.
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 ONCOLOGY: Angiogenesis Inhibitors Revived, Revealed in Progress Against Cancer
As the first FDA-approved anti-angiogenesis drug hit the market last month, Harvard researchers described advances in targeting tumor angiogenesis to fight cancer. Judah Folkman (right) and colleagues have revamped a discarded angiogenesis inhibitor, setting it on a path back to the clinic. By adding a bulky molecular chain to the small inhibitor TNP-470, the scientists eliminated the neurotoxicity that ended clinical development of the original compound without affecting its antitumor activity. In addition, for the first time, Rakesh Jain (left) and collaborators observed an angiogenesis inhibitor at work in human tumors. In their study, anti-angiogenic treatment dropped the internal pressure of tumors, opening a window of opportunity for easier delivery of chemotherapy. Jain's and Folkman' s work appears in Nature Medicine in February and March.
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Copyright 2004 by the President and Fellows of Harvard College
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