Signals and prepatterns: new insights into organ polarity in plants
- 1Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;
- 2Watson School of Biological Sciences, Cold Spring Harbor, New York 11724, USA
Abstract
The flattening of leaves results from the interaction between upper (adaxial) and lower (abaxial) domains in the developing primordium. These domains are specified by conserved, overlapping genetic pathways involving several distinct transcription factor families and small regulatory RNAs. Polarity determinants employ a series of antagonistic interactions to produce mutually exclusive cell fates whose positioning is likely refined by signaling across the adaxial–abaxial boundary. Signaling candidates include a mobile small RNA—the first positional signal described in adaxial–abaxial polarity. Possible mechanisms to polarize the incipient primordium are discussed, including meristem-derived signaling and a model in which a polarized organogenic zone prepatterns the adaxial–abaxial axis.
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Footnotes
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↵3 Corresponding author.
E-MAIL timmerma{at}cshl.edu; FAX (516) 367-8369.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.1819909.
- Copyright © 2009 by Cold Spring Harbor Laboratory Press