WINDOW OF FATE : In the NB7-1 neural progenitor cell, during the first two cell divisions, when the Hunchback gene (hb) is active and the cell triggers production of U1 and U2 motor neurons, hb is located in the interior of the nucleus (1). It remains there for an additional three cell divisions, during which it is no longer transcribed and the progenitor makes different motor neurons (2). After five cell divisions, the progenitor can no longer generate motor neurons, and hb moves to the nuclear lamina, where it becomes permanantely silenced (3). This suggests that the ability of neural stem cells to make different types of neurons is regulated by the relocation of genes to the nuclear periphery. PRECISION GRAPHICS
The paper
M. Kohwi et al., “Developmentally regulated subnuclear genome reorganization restricts neural progenitor competence in Drosophila,” Cell, 152:97-108, 2013.
Stem or progenitor cells give rise to different types of cells at different stages of development. Over time, they can lose the ability to generate some of these cell fates. Understanding how progenitor cells lose this potential, and how it might be regained, has implications for the therapeutic use of stem cells. But little is known about the mechanisms by which this “loss of competence” is regulated.
To find out, Chris Doe and Minoree Kohwi of the University of Oregon looked at neural progenitor cells called NB7-1 neuroblasts in Drosophila embryos. As they divide, these neuroblasts give rise to smaller cells that form different types ...
