Editors' ChoicePlant biology

That’s Far Enough

Science's STKE  24 Apr 2007:
Vol. 2007, Issue 383, pp. tw144
DOI: 10.1126/stke.3832007tw144

In the developing root tip of Arabidopsis, the transcription factor SHR moves from cell to cell. However, the cells that are the target of this mobile transcription signal form a layer that is only one cell thick. Cui et al. now elucidate the interactions that send the mobile signal just so far, and no further. When SHR moves to the adjacent layer of cells, it meets its mate, the SCR protein, to which it binds. Together, SHR and SCR move to the nucleus and regulate transcription of the SCR gene. An excess of SCR protein scavenges the peripatetic SHR, and with more SCR available on demand, SHR and its developmental signal cannot move out any further than that first cell layer.

H. Cui, M. P. Levesque, T. Vernoux, J. W. Jung, A. J. Paquette, K. L. Gallagher, J. Y. Wang, I. Blilou, B. Scheres, P. N. Benfey, An evolutionarily conserved mechanism delimiting SHR movement defines a single layer of endodermis in plants. Science 316, 421-425 (2007). [Abstract] [Full Text]

L. Dolan, SCARECROWs at the border. Science 316, 377-378 (2007). [Summary] [Full Text]