Establishing leaf polarity: the role of small RNAs and positional signals in the shoot apex.
The flattening of leaves results from the juxtaposition of upper (adaxial) and lower (abaxial) domains in the developing leaf primordium. The adaxial-abaxial axis reflects positional differences in the leaf relative to the meristem and is established by redundant genetic pathways that interpret this asymmetry through instructive, possibly non-cell autonomous, signals. Small RNAs have been found to play a crucial role in this process, and specify mutually antagonistic fates. Here, we review both classical and recently-discovered factors that contribute to leaf polarity, as well as the candidate positional signals that their existence implies.
Chitwood
Daniel H
DH
Cold Spring Harbor Laboratory, One Bungtown Road, Cold Spring Harbor, NY 11724, USA.
Guo
Mengjuan
M
Nogueira
Fabio T S
FT
Timmermans
Marja C P
MC
D016764:Cell Polarity; D018506:Gene Expression Regulation, Plant; D035683:MicroRNAs / Q000502:physiology; D018515:Plant Leaves / Q000254:growth & development / Q000502:physiology*; D018520:Plant Shoots / Q000254:growth & development / Q000502:physiology*; D015398:Signal Transduction
D035683:MicroRNAs