Many of modes of transport for an embryo's signals
Vogel, G.
Science 285(5430): 1003 1005
1999
ISSN/ISBN: 0036-8075 PMID: 10475837 Document Number: 506872
Developing embryos may actively transport important signaling molecules rather than relying on diffusion to carry the messages. A developing embryo undergoes major structural changes that are orchestrated by protein messengers that flow within and between cells, directing each change in cell shape and cell division. Conventional theory holds that these messenger molecules diffuse freely from their sources such that nearby cells receive the largest dose and feel the strongest effects. Such simple gradients cannot explain the physical changes associated with some crucial developmental events, however. Recent work by Thomas Kornberg of the University of California, San Francisco, suggests that rather than waiting for signals to reach them by diffusion, target cells may send out long, thin extensions to pick up messages from the source cells.