Inactivation of Suppressor Gene Prompts Formation of Cortical Stem Cells

Researchers studying the development of the embryonic nervous system have found that the Foxg1 gene suppresses development of the earliest layer of cortical cells after their formation and prevents their appearance in subsequent layers of nerve cells. Reversing the activity of this gene could allow for the development of stem cells that could be used to replace damaged nerves.

Investigators at the New York University School of Medicine (NY, USA) genetically engineered a line of mice lacking Foxg1. They reported in the January 2, 2004, issue of Science that these mice not only developed the first layer of cortical cells made up primarily of Cajal-Retzius (CR) cells, but that contrary to the situation in normal animals, subsequent cortical layers also contained CR cells.

In other experiments, the investigators inactivated Foxg1 in older cortical cells. These cells then regressed to the stage of CR cells. "What we found was a complete surprise,” explained senior author Dr. Gordon Fishell, associate professor of cell biology at New York University School of Medicine. "No one had believed that it was possible to push back the birth date of a cortical neuron. Consequently, while some populations of stem cells exist in the adult brain, these cells are restricted to producing only a subset of cell types. If one's goal is to produce cells for replacement therapy, some method must be found to turn back the clock and allow adult stem cells to give rise to the wide variety of cells made during normal brain development.”




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New York University School of Medicine