|
|
|
|||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online 11 July 2007
doi: 10.1242/dev.006296
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

Stanford University, Department of Biological Sciences, Stanford, CA 94305, USA.
Author for correspondence (e-mail:
dbergmann{at}stanford.edu)
Accepted 2 June 2007
Complex organisms consist of a multitude of cell types arranged in a precise spatial relation to each other. Arabidopsis roots generally exhibit radial tissue organization; however, within a tissue layer, cells are not identical. Specific vascular cell types are arranged in diametrically opposed longitudinal files that maximize the distance between them and create a bilaterally symmetric (diarch) root. Mutations in the LONESOME HIGHWAY (LHW) gene eliminate bilateral symmetry and reduce the number of cells in the center of the root, resulting in roots with only single xylem and phloem poles. LHW does not appear to be required for the creation of any specific cell type, but coordinately controls the number of all vascular cell types by regulating the size of the pool of cells from which they arise. We cloned LHW and found that it encodes a protein with weak sequence similarity to basic helix-loop-helix (bHLH)-domain proteins. LHW is a transcriptional activator in vitro. In plants, LHW is nuclear-localized and is expressed in the root meristems, where we hypothesize it acts independently of other known root-patterning genes to promote the production of stele cells, but might also indirectly feed into established regulatory networks for the maintenance of the root meristem.
Key words: Arabidopsis, Root pattern, Symmetry, Vasculature
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?
This article has been cited by other articles:
![]() |
B. Parizot, L. Laplaze, L. Ricaud, E. Boucheron-Dubuisson, V. Bayle, M. Bonke, I. De Smet, S. R. Poethig, Y. Helariutta, J. Haseloff, et al. Diarch Symmetry of the Vascular Bundle in Arabidopsis Root Encompasses the Pericycle and Is Reflected in Distich Lateral Root Initiation Plant Physiology, January 1, 2008; 146(1): 140 - 148. [Abstract] [Full Text] [PDF] |
||||