A big surprise: Young nerve cells can rewind their developmen...( hizophrenia and epilepsy. ...)

In subsequent experiments, the researchers asked how the overproduction of CR cells occurs. They used a clever biochemical manipulation that served as a kind of genetic stop watch, allowing them to temporarily turn off the Foxg1 gene in late progenitor cells, after the normal birth date of CR cells had passed. In this way, they observed that cortical cells destined to become layer 5 became CR cells instead. Apparently, the gene orchestrates the program responsible for ensuring that the cortical layers of the cerebral cortex are laid down in a precise sequence. When the gene is inactivated or turned off, the program seems to revert to its earliest stage.

The researchers do not know how late in the game they can play their genetic tricks. If they turn off the Foxg1 gene at a later time in development, such as when cortical layers 2 or 3 are forming, will progenitor neuronal cells still become CR cells? Are there other genes that control the developmental clock? If such genes exist, it may be possible to turn these genes off in adult neural stem cells, and thereby generate a far broader array of tissue than otherwise possible. "I would say that the chances of this happening are very remote," says Dr. Fishell, "but then again, I never thought that the clock could have been turned back in neuronal progenitor cells."

The authors of the study are Gordon Fishell and Carina Hanashima of NYU School of Medicine; Eseng Lai of Merck; Suzanne Li of Memorial Sloan-Kettering Cancer Center; and Lijian Shen of Weill Medical College of Cornell University.

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Contact: Pamela McDonnell
Pamela.Mcdonnell@med.nyu.edu
212-404-3555
New York University Medical Center and School of Medicine
1-Jan-2004